BSc CSIT Entrance Exam 2075 Questions with Answers

1. a$a\neq0,\ b=0$
2. b$a=0,\ b=0$
3. c$a=0,\ b\neq0$
4. d$a\neq0,\ b\neq0$

Answer (c): A fraction is zero only when the numerator is zero, and the denominator must be non-zero for the fraction to exist.

Revise: Algebra (Class 11 notes)

1. a$-5$
2. b$6$
3. c$0$
4. d$[5,\infty)$

Answer (b): The inequality $x\ge5$ is satisfied by the single number 6, while $[5,\infty)$ is the whole set of solutions rather than a value of $x$.

Revise: Algebra (Class 11 notes)

1. a${5}$
2. b${-2,5}$
3. c${-2,-5}$
4. d${-3,7}$

Answer (d): $x-2=\pm5$ gives $x=7$ or $x=-3$.

Revise: Algebra (Class 11 notes)

1. a${1,2,3}$
2. b${1,2,3,4}$
3. c${2,3,4}$
4. d$\mathbb{R}$

Answer (c): The range is the set of second elements: ${2,3,4}$.

Revise: Algebra (Class 11 notes)

1. a$4$
2. b$3$
3. c$81$
4. d$a$

Answer (b): Put $x=4,y=81$: $a^4=81=3^4$, so $a=3$.

Revise: Algebra (Class 11 notes)

1. a$n\pi\pm\pi/4$
2. b$n\pi+\pi/4$
3. c$n\pi-\pi/4$
4. d$\pm\pi/4$

Answer (a): $\tan^2x=\tan^2(\pi/4)$ gives the general solution $x=n\pi\pm\pi/4$.

Revise: Trigonometry (Class 11 notes)

1. a$\sqrt{1-x^2}$
2. b$2\sqrt{1-x^2}$
3. c$2x\sqrt{1-x^2}$
4. d$\sqrt{2x(1-x^2)}$

Answer (c): Let $\theta=\sin^{-1}x$. Then $\sin2\theta=2\sin\theta\cos\theta=2x\sqrt{1-x^2}$.

Revise: Trigonometry (Class 11 notes)

1. a$5$
2. b$-5$
3. c$-\frac15$
4. d$\frac13$

Answer (d): $a=\frac14$, $r=\frac14$, so $S_\infty=\frac{a}{1-r}=\frac{1/4}{3/4}=\frac13$.

Revise: Algebra (Class 11 notes)

1. a$15$
2. b$2$
3. c$9$
4. d$10$

Answer (a): For an A.P. the middle term is the mean of the others: $2(6a-2)=(8a+4)+(3a+7)$, so $12a-4=11a+11$ and $a=15$.

Revise: Algebra (Class 11 notes)

1. a$10$
2. b$15$
3. c$0$
4. d$20$

Answer (c): Row 3 is twice row 2, so two rows are proportional and the determinant is 0.

Revise: Algebra (Class 12 notes)

1. a$(4)$
2. b$(14)$
3. c$(0)$
4. d$(15)$

Answer (b): $AB=1\cdot1+2\cdot2+3\cdot3=14$, a $1\times1$ matrix.

Revise: Algebra (Class 12 notes)

1. a$\begin{bmatrix}-3&1\1&-1\end{bmatrix}$
2. b$\frac12\begin{bmatrix}-3&-1\-1&-1\end{bmatrix}$
3. c$\begin{bmatrix}-3&-1\-1&-1\end{bmatrix}$
4. d$\frac12\begin{bmatrix}-1&1\1&-3\end{bmatrix}$

Answer (b): Determinant $=3-1=2$. Swap the diagonal, negate the off-diagonal: $\frac12\begin{bmatrix}-3&-1\-1&-1\end{bmatrix}$.

Revise: Algebra (Class 12 notes)

1. a$0$
2. b$-8$
3. c$1$
4. d$8$

Answer (b): $1+\omega^2=-\omega$, so $1-\omega+\omega^2=-2\omega$ and $(-2\omega)^3=-8\omega^3=-8$.

Revise: Algebra (Class 12 notes)

1. a$\frac12$
2. b$\sqrt2$
3. c$\frac1{\sqrt2}$
4. d$2$

Answer (c): $|1/(1+i)|=1/|1+i|=1/\sqrt2$.

Revise: Algebra (Class 12 notes)

1. a$x^2-7x-12=0$
2. b$x^2-7x+12=0$
3. c$x^2+7x+12=0$
4. d$x^2+7x-12=0$

Answer (b): The equation is $x^2-(3+4)x+3\cdot4=0$, that is $x^2-7x+12=0$.

Revise: Algebra (Class 11 notes)

1. a$-1$
2. b$\frac15$
3. c$2$
4. d$3$

Answer (b): $d=\frac{|3(-1)+4(-2)+12|}{\sqrt{9+16}}=\frac{1}{5}$.

Revise: Analytic geometry (Class 11 notes)

1. a$-3$
2. b$3$
3. c$0$
4. d$1$

Answer (b): Perpendicular lines need coefficient sum $a+b=0$: $k-3=0$, so $k=3$.

Revise: Analytic geometry (Class 11 notes)

1. a$2x+y=5$
2. b$x+y=5$
3. c$2x-y=5$
4. d$x-y=5$

Answer (a): Tangent at $(x_1,y_1)$ is $xx_1+yy_1=5$, i.e. $2x+y=5$.

Revise: Analytic geometry (Class 11 notes)

1. a$1$
2. b$0$
3. c$\infty$
4. d$2$

Answer (a): $\frac{x^2+x}{x^2}=1+\frac1x\to1$.

Revise: Calculus (Class 11 notes)

1. a$0$
2. b$1$
3. c$2$
4. d$-2$

Answer (c): $\sec^2x-2=\tan^2x-1=(\tan x-1)(\tan x+1)$, so the limit is $\tan\frac\pi4+1=2$.

Revise: Calculus (Class 11 notes)

1. a$1$
2. b$-\frac{2}{x^3}$
3. c$\frac{2}{x^2}$
4. d$\frac{2}{x^3}$

Answer (b): $y=1/t=x^{-2}$, so $dy/dx=-2x^{-3}=-2/x^3$.

Revise: Calculus (Class 11 notes)

1. a$0$
2. b$1$
3. c$2x$
4. d$-1$

Answer (d): $\frac{d(x^2)}{d(-x^2)}=\frac{2x}{-2x}=-1$.

Revise: Calculus (Class 11 notes)

1. a$0$
2. b$\log2$
3. c$2$
4. d$1$

Answer (a): The integrand is an odd function and the limits are symmetric, so the integral is 0.

Revise: Calculus (Class 12 notes)

1. a$-\frac{1}{1+\ln x}+c$
2. b$\frac{1}{1+\ln x}+c$
3. c$\frac{1}{\ln x}+c$
4. d$\frac{1}{x(1+\ln x)}+c$

Answer (a): Put $u=1+\ln x$, $du=dx/x$: $\int u^{-2}du=-1/u+c$.

Revise: Calculus (Class 12 notes)

1. a$64$
2. b$84$
3. c$16$
4. d$-84$

Answer (b): $\int_1^4 4x^2dx=\frac43(64-1)=84$.

Revise: Calculus (Class 12 notes)

1. a$[M^0L^0T^0]$
2. b$[L]$
3. c$[L^{-1}]$
4. d$[MT^{-2}]$

Answer (b): Tension is a force with dimension $[MLT^{-2}]$ and surface tension is $[MT^{-2}]$, so their ratio has dimension $[L]$.

Revise: Physical Quantities (Class 11 notes)

1. a$50$ m/s$^2$
2. b$2$ m/s$^2$
3. c$5$ m/s$^2$
4. d$0.5$ m/s$^2$

Answer (c): Mass $=10/10=1$ kg (taking $g=10$), so $a=F/m=5$ m/s$^2$.

Revise: Dynamics (Class 11 notes)

1. a$R$
2. b$\sqrt2R$
3. c$R/2$
4. d$R/4$

Answer (c): $g'=g(1-d/R)=g/2$ gives $d=R/2$.

Revise: Gravitation (Class 11 notes)

1. aincrease mass
2. bgive better mass
3. cincrease moment of inertia
4. ddrive easily

Answer (c): Spokes keep the mass near the rim, so the wheel has a large moment of inertia and runs steadily.

Revise: Rotational Dynamic (Class 12 notes)

1. aincrease
2. bdecrease
3. cremain same
4. ddepend upon nature of matter

Answer (c): Young's modulus is a property of the material, independent of length and diameter.

Revise: Elasticity (Class 11 notes)

1. a$1.01\times10^{-7}$ N
2. b$1.01\times10^{-8}$ N
3. c$1.6\times10^{-9}$ N
4. d$1.6\times10^{-8}$ N

Answer (a): $\eta=18\times10^{-6}$ Pa s. $F=6\pi\eta rv=6\pi(18\times10^{-6})(0.3\times10^{-3})(1)\approx1.01\times10^{-7}$ N.

Revise: Fluid Statics (Class 12 notes)

1. aaluminum
2. binvar
3. csteel
4. dnickel

Answer (b): Invar (an iron-nickel alloy) has a very small coefficient of linear expansion.

Revise: Thermal Expansion (Class 11 notes)

1. a$47^\circ$C
2. b$77^\circ$C
3. c$102^\circ$C
4. d$127^\circ$C

Answer (d): Three-fourths of the air remains, so $T'=300\times\frac43=400$ K $=127^\circ$C.

Revise: Ideal Gas (Class 11 notes)

1. a$0$ K
2. b$0^\circ$C
3. cequal to source
4. dnone of above

Answer (a): $\eta=1-T_2/T_1=1$ only when $T_2=0$ K.

Revise: Second Law of Thermodynamics (Class 12 notes)

1. a$920$ K
2. b$1125$ K
3. c$1025$ K
4. d$1320$ K

Answer (c): Area $=2\pi rl=2\pi(6\times10^{-3})(0.6)=2.26\times10^{-2}$ m$^2$. $T^4=\frac{1500}{6\times10^{-8}\times2.26\times10^{-2}}\approx1.1\times10^{12}$, so $T\approx1025$ K.

Revise: Rate of Heat Flow (Class 11 notes)

1. a$14.5^\circ$
2. b$30^\circ$
3. c$42^\circ$
4. d$62^\circ$

Answer (b): $a\sin\theta=2\lambda$: $\sin\theta=\frac{2\times550}{2200}=0.5$, so $\theta=30^\circ$.

Revise: Diffraction of Light (Class 12 notes)

1. a$-40$ cm
2. b$+40$ cm
3. c$-25$ cm
4. d$+25$ cm

Answer (a): $P=5-7.5=-2.5$ D, so $f=1/P=-0.4$ m $=-40$ cm.

Revise: Lenses (Class 11 notes)

1. a$2.4$ cm
2. b$2.1$ cm
3. c$1.5$ cm
4. d$1.8$ cm

Answer (d): Relaxed eye: $v_0=L-f_e=9$ cm. $M=\frac{v_0}{u_0}\cdot\frac{D}{f_e}=25$ gives $\frac{v_0}{u_0}=5$, so $u_0=9/5=1.8$ cm.

Revise: Lenses (Class 11 notes)

1. a$0.7$ cm
2. b$1.2$ cm
3. c$70$ cm
4. d$12$ cm

Answer (d): $\lambda=v/f=360/500=0.72$ m. A phase difference of $60^\circ$ is $\lambda/6$, so the distance is $0.72/6=0.12$ m $=12$ cm.

Revise: Wave Motion (Class 12 notes)

1. adecreased
2. bincreases
3. cremains same
4. dzero

Answer (b): Like charges repel, so work is done against the force and the potential energy rises.

Revise: Potential Difference and Potential Energy (Class 11 notes)

1. a$n^2$
2. b$1/n^2$
3. c$n$
4. d$1/n$

Answer (a): Parallel: $nC$ (maximum). Series: $C/n$ (minimum). Ratio $=nC\div(C/n)=n^2$.

Revise: Capacitor (Class 11 notes)

1. a$12\ \Omega$
2. b$9\ \Omega$
3. c$6\ \Omega$
4. d$3\ \Omega$

Answer (d): Each semicircle is $6\ \Omega$, and the two are in parallel: $\frac{6\times6}{12}=3\ \Omega$.

Revise: DC Circuit (Class 11 notes)

1. a$0$
2. blow
3. chigh
4. dinfinite

Answer (a): An ideal ammeter is connected in series and must not change the current, so its resistance is zero.

Revise: DC Circuit (Class 11 notes)

1. a$18$ cm
2. b$16$ cm
3. c$11$ cm
4. d$9$ cm

Answer (c): $v=\sqrt{2E/m}=\sqrt{\frac{2\times10\times1.6\times10^{-19}}{9.1\times10^{-31}}}\approx1.88\times10^{6}$ m/s. $r=\frac{mv}{eB}\approx0.107$ m $\approx11$ cm.

Revise: Magnetic Field (Class 12 notes)

1. afor a short time
2. bfor a long time
3. cforever
4. dso long as the change in flux takes place

Answer (d): By Faraday's law the emf exists only while the flux is changing.

Revise: Electromagnetic Induction (Class 12 notes)

1. apermanent magnet
2. belectromagnet
3. ctransformer
4. dnone of above

Answer (a): High retentivity means the material keeps its magnetism, which is what a permanent magnet needs.

Revise: Magnetic Properties of Materials (Class 12 notes)

1. atype of glass
2. bglass used for the tube
3. cthe gas in the tube
4. dpressure inside the tube

Answer (c): The glow comes from excited gas atoms, so its colour is set by the gas.

Revise: Electrons (Class 12 notes)

1. aFrequency
2. bintensity
3. cwork function
4. dmomentum

Answer (a): $K_{max}=hf-\phi$ depends on frequency (and on work function), not on intensity.

Revise: Photons (Class 12 notes)

1. a$5\times10^{17}$
2. b$5\times10^{16}$
3. c$5\times10^{15}$
4. d$5\times10^{14}$

Answer (d): Energy per fission $=200\times1.6\times10^{-13}=3.2\times10^{-11}$ J. $N=\frac{16000}{3.2\times10^{-11}}=5\times10^{14}$.

Revise: Nuclear Physics (Class 11 notes)

1. aaluminum
2. boxygen
3. cphosphorus
4. dcopper

Answer (a): A trivalent impurity (aluminium) creates holes and gives p-type silicon.

Revise: Semiconductor Devices (Class 12 notes)

1. aLet up
2. bLet off
3. cLet on
4. dLet down

Answer (c): 'Let on' means to reveal a secret, so 'I won't let on to anyone' fits the promise.

Revise: Grammar and Usage (Class 11 notes)

1. atie down
2. btie in with
3. ctie up
4. dthrow out

Answer (a): 'Tie down' means to restrict someone, so 'feel tied down by my presence' matches 'go out whenever you like'.

Revise: Grammar and Usage (Class 11 notes)

1. ashow off
2. bshut up
3. csettle up
4. dshow up

Answer (d): 'Show up' means appear or arrive.

Revise: Grammar and Usage (Class 11 notes)

1. acall for
2. bcall by
3. ccall on
4. dcall up

Answer (b): 'Call by' means to visit briefly and needs no object, so it completes 'Mahesh is calling by this evening'; the other options need an object.

Revise: Grammar and Usage (Class 11 notes)

1. adismal
2. bhazy
3. cprecept
4. dinflated

Answer (d): Magniloquent means using high-flown, pompous language, so 'inflated' is closest.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. agay
2. boffence
3. cdepressed
4. dfaint

Answer (c): Vivacious means lively and high-spirited; the opposite is depressed.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. afalse
2. bveracious
3. cobstinate
4. dvenal

Answer (b): Mendacious means lying; its opposite is veracious (truthful).

Revise: Vocabulary and Word Formation (Class 11 notes)

1. ataciturn
2. btarnish
3. cblemish
4. dhot

Answer (a): Taciturn means habitually silent and reserved.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. afor, in
2. bfor, of
3. cof, after
4. dof, in

Answer (b): The fixed phrases are 'cause for anxiety' and 'take care of your health'.

Revise: Grammar and Usage (Class 11 notes)

1. ato, for
2. bfor, in
3. cwith, for
4. dfor, to

Answer (c): 'Sympathy with' (fellow feeling) pairs with 'taste for music' (liking), giving 'with, for'.

Revise: Grammar and Usage (Class 11 notes)

1. ato, on
2. bfor, to
3. cby, to
4. dto, to

Answer (d): The idioms are 'contrary to' and 'turn a deaf ear to', so both gaps take 'to'.

Revise: Grammar and Usage (Class 11 notes)

1. ato, for
2. bto, to
3. cfor, for
4. don, at

Answer (a): We say 'addicted to drugs' and 'anxious for (about) their future'.

Revise: Grammar and Usage (Class 11 notes)

1. aat, to
2. bupon, into
3. con, to
4. dat, in

Answer (b): 'Touch upon' a subject and 'turn into' something.

Revise: Grammar and Usage (Class 11 notes)

1. azoophobia
2. bhydrophobia
3. cclaustrophobia
4. dpedophobia

Answer (c): Claustrophobia is the fear of confined spaces.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aprecious
2. ba great work
3. cmiraculous
4. dsignificant

Answer (b): Latin for 'great work': the finest work of an artist or writer.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. auxoricide
2. bhomicide
3. cfilicide
4. dsorricide

Answer (a): Uxoricide is wife-killing (homicide = any person, filicide = child).

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aaviary, zoo
2. bapiary, aquarium
3. ccemetery, depot
4. ddispensary, garage

Answer (b): An apiary houses bees; an aquarium houses fish.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aswear sometimes
2. bspeak very fast
3. cuse swear words frequently
4. duse harsh words

Answer (c): 'To swear like a trooper' means to use swear words very frequently.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aone in best emotional and physical condition
2. bsecure and stable
3. cquick and intelligent
4. dreserved and shy

Answer (a): The idiom means perfectly healthy and well.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aa bad time
2. bbe in prison / serve a prison sentence
3. cpresent time service
4. dpleasant time

Answer (b): To 'do time' or 'serve time' means to be in prison.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. ago out for entertainment
2. bsleep well
3. cstop some activity, work etc. to go to bed
4. ddrink before night

Answer (c): It means to stop what you are doing and go to bed.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aignore unwelcome things
2. blisten attentively
3. cplay an instrument from memory
4. dAct according to the situation

Answer (d): 'To play it by ear' means to improvise and act according to the situation.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aimportant occasion
2. bhave no money in one's bank account, owe money to the bank
3. ca sign of welcome
4. dvery angry

Answer (b): Being 'in the red' means being overdrawn or in debt.

Revise: Vocabulary and Word Formation (Class 11 notes)

1. aHe said that congratulations.
2. bHe congratulated me.
3. cHe congratulated that I Passed.
4. dHe said that I deserved congratulations.

Answer (b): A greeting such as 'Congratulations' is reported with the verb 'congratulated'.

Revise: Grammar and Usage (Class 11 notes)

1. a$1.0$ g
2. b$0.5$ g
3. c$1.6\times10^{-24}$ g
4. d$3.2\times10^{-24}$ g

Answer (c): $\frac{1.008\ \mathrm{g}}{6.022\times10^{23}}\approx1.67\times10^{-24}$ g.

Revise: Stoichiometry (Class 11 notes)

1. aAtomic weight
2. bequivalent weight
3. catomic volume
4. datomic number

Answer (d): Atomic number is the count of protons, so it is always an integer.

Revise: Atomic Structure (Class 11 notes)

1. aSize of the orbital
2. bShape of the orbital
3. cEnergy of orbitals
4. dOrientation of the orbital in space

Answer (b): The azimuthal quantum number $l$ gives the shape (s, p, d, f) of the orbital.

Revise: Atomic Structure (Class 11 notes)

1. apH increases but pOH decreases
2. bpH decreases but pOH increases
3. cboth pH and pOH increases
4. dboth pH and pOH decreases

Answer (d): $K_w$ rises with temperature, so $[H^+]=[OH^-]$ both rise and both pH and pOH fall, while water stays neutral.

Revise: Ionic Equilibrium (Class 12 notes)

1. aNe
2. bMg
3. cCl
4. dNa

Answer (a): Noble gas neon has a complete octet and small size, giving the highest first ionization energy here.

Revise: Classification of Elements (Class 11 notes)

1. a$\ce{Na2SO4}$
2. b$\ce{(NH4)2SO4}$
3. c$\ce{FeSO4}$
4. d$\ce{ZnSO4}$

Answer (a): $\ce{Na2SO4}$ comes from a strong acid and strong base, so there is no hydrolysis.

Revise: Ionic Equilibrium (Class 12 notes)

1. a$75$ minutes
2. b$100$ minutes
3. c$200$ minutes
4. d$300$ minutes

Answer (b): Half-life is 50 min. $75%$ completion needs two half-lives: $2\times50=100$ min.

Revise: Chemical Kinetics (Class 12 notes)

1. aFe
2. bZn
3. cCu
4. dHg

Answer (c): Malachite is $\ce{CuCO3.Cu(OH)2}$, an ore of copper.

Revise: Chemistry of Metals (Class 11 notes)

1. aSilica
2. bCoal
3. cLimestone
4. dCO

Answer (d): Carbon monoxide formed in the furnace is the actual reducing agent: $\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}$.

Revise: Chemistry of Metals (Class 11 notes)

1. a$1.0$ M
2. b$0.5$ M
3. c$2.0$ M
4. d$0.1$ M

Answer (b): Equal volumes of 1.0 M solutions make 0.5 M of each reactant and the same amount of NaCl, so the volume doubles and $[\text{NaCl}]=1.0/2=0.5$ M.

Revise: Volumetric Analysis (Class 12 notes)

1. aFe powder
2. bNi powder
3. cZnO
4. d$\ce{V2O5}$

Answer (d): The contact process uses vanadium pentoxide (formerly platinum).

Revise: Chemistry of Non-Metals (Class 11 notes)

1. a$1.0$
2. b$0.0$
3. c$2.0$
4. d$3.0$

Answer (d): Molecularity is the number of reacting molecules: $2+1=3$.

Revise: Chemical Kinetics (Class 12 notes)

1. aDeuterium oxide ($\ce{D2O}$)
2. bWater in which heavier salts are dissolved
3. c$\ce{H3O}$
4. dWater formed by the combination of hydrogen and heavier isotope of oxygen

Answer (a): Heavy water is water made from deuterium, $\ce{D2O}$.

Revise: Chemistry of Non-Metals (Class 11 notes)

1. aSurface coating
2. bElectroplating
3. cSherardizing
4. dGalvanizing

Answer (d): Zinc coating of iron is galvanizing.

Revise: Electrochemistry (Class 12 notes)

1. a$\ce{NaHCO3}$ and NaOH
2. b$\ce{Na2CO3}$ and $\ce{NaHCO3}$
3. c$\ce{Na2CO3}$ and NaOH
4. d$\ce{NaHCO3}$ and NaCl

Answer (a): The acid salt and base react: $\ce{NaHCO3 + NaOH -> Na2CO3 + H2O}$.

Revise: Ionic Equilibrium (Class 12 notes)

1. aTautomerism
2. bInductive effect
3. cMetamerism
4. dResonance

Answer (d): Delocalised pi electrons (resonance) make all C-C bonds equal.

Revise: Aromatic Hydrocarbons (Class 11 notes)

1. aEthanoic acid
2. bOxalic acid
3. cLactic acid
4. dPicric acid

Answer (d): Picric acid is 2,4,6-trinitrophenol, a phenol with no carboxyl group.

Revise: Phenols (Class 12 notes)

1. aAlcohol
2. balkyl nitrite
3. cSecondary
4. dNitro alkane

Answer (a): Primary aliphatic amines give diazonium salts that decompose to alcohols with $\ce{N2}$.

Revise: Amines (Class 12 notes)

1. aWurtz reaction
2. bRiemer-Tiemann reaction
3. cCannizzaro reaction
4. dAldol condensation

Answer (c): In the Cannizzaro reaction one aldehyde molecule is oxidised to acid and another reduced to alcohol.

Revise: Aldehydes and Ketones (Class 12 notes)

1. aElectrophilic addition
2. bElectrophilic substitution
3. cNucleophilic addition
4. dNucleophilic substitution

Answer (b): $\ce{NO2+}$ attacks the ring and replaces H.

Revise: Aromatic Hydrocarbons (Class 11 notes)

1. aAmpicillin
2. bAcetyl salicylic acid
3. cParacetamol
4. dChloroxylenol

Answer (d): Dettol contains chloroxylenol as the active antiseptic.

Revise: Chemistry in the Service to Mankind (Class 12 notes)

1. aInsecticide
2. bdye
3. csynthetic polymer
4. dantiseptic drug

Answer (a): DDT is a chlorinated organic insecticide.

Revise: Chemistry in the Service to Mankind (Class 12 notes)

1. aGlucose
2. bDNA
3. cSoap
4. dGlycine hydrochloride

Answer (d): A zwitter ion carries both a positive and a negative charge, and amino acids such as glycine are the standard example. Glycine hydrochloride is the only amino acid option; glucose, DNA and soap are not zwitter ions.

Revise: Amines (Class 12 notes)

1. aAldose
2. bKetose
3. cPentose
4. dHexose

Answer (b): Fructose has its carbonyl group in the middle of the chain, so it is a ketose (it is also a hexose, but ketose is the distinguishing class).

1. a$\mathrm{sec^{-1}}$
2. b$\mathrm{mol\ sec^{-1}}$
3. c$\mathrm{mol^{-1}\ sec^{-1}}$
4. d$\mathrm{liter^{2}\ mol^{-2}\ s^{-1}}$

Answer (a): $k=\text{rate}/[A]$ has units $\mathrm{mol,L^{-1}s^{-1}}/\mathrm{mol,L^{-1}}=\mathrm{s^{-1}}$.

Revise: Chemical Kinetics (Class 12 notes)