391.

The half-life period of a first order reaction having rate constant k = 0.231 × 10^-10 s^-1  will be

• 32 × 10¹⁰ s

• 2 × 10¹⁰ s

• 3 × 10¹⁰ s

• 2 × 10^-10 s

For the reaction X → Y, the concentrations of 'X' are 1.2 M, 0.6 M, 0.3 Mand 0.15 M at 0, 1, 2 and 3 hours respectively. The order of the reaction is

• zero

• half

• one

• two

In a reaction, 2A + B → 3C, the concentration of A decreases from 0.5 mol L^-1 to 0.3 mol L^-1 in 10 minutes. The rate of production of 'C' during this period is

• 0.01 mol L^-1 min^-1

• 0.04 mol L^-1 min^-1

• 0.05 mol L^-1 min^-1

• 0.03 mol L^-1 min^-1

Ammonium ion (NH₄⁺) reacts with nitrite ion (NO${}_2^{-}$) in aqueous solution according to the equation

NH₄⁺ (aq) + NO${}_2^{-}$ (aq) → N₂ (g) + 2H₂O (l)

The following initial rates of reaction have been measured for the given reactant concentrations.

Which of the following is the rate law for this reaction?

• Rate = k[NH₄⁺][NO${}_2^{-}$]⁴

• Rate = k [NH${}_4^{+}$][NO${}_2^{-}$]

• Rate = k [NH${}_4^{+}$][NO${}_2^{-}$]²

• Rate = k[NH${}_4^{+}$]²[NO${}_2^{-}$]

The work function of a metal is 5 eV. What is the kinetic energy of the photoelectron ejected from the metal surface if the energy of the incident radiation is 6.2 eV? (1 eV = 1.6 × 10^-19)

• 1.92 × 10^-19 J

• 6.626 × 10^-19 J

• 8.10 × 10^-19 J

• 1.92 × 10^-18 J

The change in potential of the half-cell Cu²⁺|Cu when aqueous Cu²⁺ solution is diluted 100 times at 298 K? $\left(\frac{2.303 \mathrm{RT}}{\mathrm{F}} = 0.06\right)$

• increases by 120 mV

• decreases by 120 mV

• increases by 60 mV

• decreases by 60 mV

The reaction, A + B → products is first order with respect to A and second order with respect to B. When 1.0 mole each of A and B were taken in one litre flask, the initial rate of the reaction is 1.0 × 10^-2 mol L^-1 s^-1. The rate of the reaction when 50% of the reactants have been converted into products is

• 1.00 × 10^-3 mol L^-1 s^-1

• 0.05 × 10^-2 mol L^-1 s^-1

• 1.25 × 10^-3 mol L^-1 s^-1

• 4.00 × 10^-2 mol L^-1 s^-1

For the following reaction,

NO₂(g) + CO(g) → NO(g) + CO₂(g)

the rate law is Rate = k [NO₂]². If 0.1 mole of gaseous carbon monoxide is added at constant temperature to the reaction mixture which of the following statement is true?

• Both k and the reaction rate remain the same

• Both k and the reaction rate increase

• Both k and the reaction rate decrease

• Only k increases, the reation rate remain the same

The rate constant and half-life of a first order reaction are related to each other as

• ${\mathrm{t}}_{1/2}=\frac{0.693}{\mathrm{k}}$

• t_1/2 = 0.693 k

• k = 0.693 t_1/2

• ${\mathrm{kt}}_{1/2} =\frac{1}{0.693}$

Average rate of reaction for the following reaction.

$2{\mathrm{SO}}_2\left(\mathrm{g}\right) + {\mathrm{O}}_2\left(\mathrm{g}\right) \to 2{\mathrm{SO}}_3\left(\mathrm{g}\right)$ is written as

• $\frac{∆\left[{\mathrm{SO}}_2\right]}{∆\mathrm{t}}$

• $-\frac{∆\left[{\mathrm{O}}_2\right]}{∆\mathrm{t}}$

• $\frac{1}{2}\frac{∆\left[{\mathrm{SO}}_2\right]}{∆\mathrm{t}}$

• $\frac{∆\left[{\mathrm{SO}}_3\right]}{∆\mathrm{t}}$