TU IOE | Chemistry
The number of moles in 11 g of $\ce{CO2}$ (molar mass 44 g/mol) is
Answer: 0.25
Model set 1, Q64: explanation →When 6 g of carbon burns completely in excess oxygen, the mass of $\ce{CO2}$ formed is (C = 12, O = 16)
Answer: 22 g
Model set 1, Q78: explanation →The number of moles in 11 g of carbon dioxide (molar mass 44 g/mol) is
Answer: 0.25
Model set 2, Q64: explanation →The volume of hydrogen at STP liberated when 6.5 g of zinc (Zn = 65) reacts with excess dilute acid is
Answer: 2.24 L
Model set 2, Q81: explanation →The unit of the rate constant of a first-order reaction is
Answer: $\text{s}^{-1}$
Model set 1, Q71: explanation →A first-order reaction has a half-life of 20 minutes. The fraction of the reactant left after 60 minutes is
Answer: 1/8
Model set 1, Q82: explanation →The unit of the rate constant of a first order reaction is
Answer: $\mathrm{s^{-1}}$
Model set 2, Q66: explanation →A first order reaction has a half-life of 20 minutes. The time required for 87.5% of it to complete is
Answer: 60 minutes
Model set 2, Q79: explanation →For $\ce{N2 + 3H2 <=> 2NH3}$ (exothermic), increasing the pressure at constant temperature shifts the equilibrium
Answer: to the right
Model set 1, Q68: explanation →For $\ce{H2 + I2 <=> 2HI}$, equilibrium concentrations are $[\ce{H2}]=0.1$, $[\ce{I2}]=0.1$ and $[\ce{HI}]=0.4$ mol/L. The value of $K_c$ is
Answer: 16
Model set 1, Q83: explanation →For $\mathrm{N_2+3H_2\rightleftharpoons 2NH_3}$, the equilibrium concentrations are $[\mathrm{N_2}]=0.25$ M, $[\mathrm{H_2}]=2$ M and $[\mathrm{NH_3}]=2$ M. The value of $K_c$ is
Answer: 2
Model set 2, Q78: explanation →The pH of 0.01 M HCl solution is
Answer: 2
Model set 1, Q69: explanation →The pH of 0.1 M weak acid HA with $K_a=1\times10^{-5}$ is (assume dissociation is small)
Answer: 3
Model set 1, Q80: explanation →The pH of a $0.005$ M solution of Ba(OH)$_2$ (fully dissociated) is
Answer: 12
Model set 2, Q65: explanation →In a galvanic cell, oxidation takes place at the
Answer: anode
Model set 1, Q70: explanation →Given $E^\circ(\ce{Zn^2+/Zn})=-0.76$ V and $E^\circ(\ce{Cu^2+/Cu})=+0.34$ V, the standard emf of the Zn-Cu cell is
Answer: 1.10 V
Model set 1, Q81: explanation →A charge of 9650 C is passed through aqueous CuSO$_4$. The mass of copper deposited is (Cu = 63.5, F = 96500 C/mol)
Answer: 3.175 g
Model set 2, Q80: explanation →Heating a sulphide ore strongly in excess air to convert it into its oxide is called
Answer: roasting
Model set 1, Q74: explanation →The flame colour imparted by strontium salts is
Answer: crimson red
Model set 2, Q70: explanation →Froth flotation is mainly used for the concentration of
Answer: sulphide ores
Model set 2, Q71: explanation →The IUPAC name of $\ce{CH3CH(CH3)CH2CH3}$ is
Answer: 2-methylbutane
Model set 1, Q75: explanation →The IUPAC name of $\mathrm{CH_3CH(CH_3)CH_2CH_2OH}$ is
Answer: 3-methylbutan-1-ol
Model set 2, Q72: explanation →The number of structural isomers of pentane, $\mathrm{C_5H_{12}}$, is
Answer: 3
Model set 2, Q73: explanation →Which of the following gives a silver mirror with Tollens' reagent?
Answer: acetaldehyde
Model set 1, Q77: explanation →A compound $\ce{C3H6O}$ gives a positive iodoform test but does not reduce Tollens' reagent. It is
Answer: acetone
Model set 1, Q85: explanation →Acetaldehyde reacts with methylmagnesium bromide, and the adduct is hydrolysed. The product is
Answer: propan-2-ol
Model set 2, Q83: explanation →Acetamide is treated with $\ce{Br2}$ and aqueous NaOH (Hofmann bromamide reaction). The main product is
Answer: methylamine
Model set 1, Q84: explanation →The carbylamine test (CHCl$_3$ with alcoholic KOH) is given by
Answer: primary amines
Model set 2, Q76: explanation →Acetamide on heating with bromine and aqueous NaOH (Hofmann bromamide reaction) gives
Answer: methylamine
Model set 2, Q84: explanation →A gas occupying 2 L at 1 atm is compressed isothermally to 1 L. The new pressure is
Answer: 2 atm
Model set 1, Q65: explanation →Under the same conditions, the ratio of the rate of diffusion of $\ce{H2}$ to that of $\ce{O2}$ is
Answer: 4
Model set 1, Q79: explanation →The shape of the $\ce{NH3}$ molecule is
Answer: trigonal pyramidal
Model set 1, Q67: explanation →The shape of the XeF$_4$ molecule is
Answer: square planar
Model set 2, Q69: explanation →Propene reacts with HBr (no peroxide) to give mainly
Answer: 2-bromopropane
Model set 1, Q76: explanation →Hydration of propyne in the presence of dilute H$_2$SO$_4$ and HgSO$_4$ gives
Answer: propanone
Model set 2, Q74: explanation →The number of unpaired electrons in the Fe$^{3+}$ ion (atomic number 26) is
Answer: 5
Model set 2, Q68: explanation →The spin-only magnetic moment of Fe$^{2+}$ (high spin, atomic number 26) is about
Answer: 4.9 BM
Model set 2, Q85: explanation →The IUPAC name of the compound $\mathrm{CH_3CH_2CH_2CH_2Br}$ is
Answer: 1-bromobutane
Model set 2, Q77: explanation →Ethyl bromide is treated with KCN to form X, which on acid hydrolysis gives Y. Y is
Answer: propanoic acid
Model set 2, Q82: explanation →The number of neutrons in the nuclide $^{23}_{11}\text{Na}$ is
Answer: 12
Model set 1, Q66: explanation →For $A\to B$, $\Delta H=-50$ kJ and for $B\to C$, $\Delta H=+20$ kJ. For $A\to C$, $\Delta H$ is
Answer: kJ
Model set 1, Q72: explanation →The catalyst used in the Contact process for manufacturing sulphuric acid is
Answer: $\ce{V2O5}$
Model set 1, Q73: explanation →The oxidation number of chromium in K$_2$Cr$_2$O$_7$ is
Answer: +6
Model set 2, Q67: explanation →Which of the following is the strongest acid?
Answer: $\mathrm{Cl_3CCOOH}$
Model set 2, Q75: explanation →