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

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

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

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

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

The rate constant of a first order reaction is doubled when the temperature is increased from 20°C to 25°C. How many times the rate constant will increase if the temperature is raised from 20°C to 40°C? 

• 4

• 8

• 16

• 32

99.

In the following reaction, the initial concentrations of the reactant and initial rates at 298 K are given

2A → C + D

[A]0 mol L-1	Initial rate in mol L-1s-1
0.01	5.0 × 10-5
0.02	2.0 × 10-4

The value of rate constant of this reaction at 298 K is

• 0.01 s^-1

• 5 × 10^-3 mol L^-1 s^-1

• 2.0 × 10^-2 mol^-1 Ls^-1

• 5 × 10^-1 mol^-1 Ls^-1

The rate of the reaction A → products, at the initial concentration of 3.24 × 10^-2 M is nine times its rate at another initial concentration of 1.2 × 10^-3 M. The order of the reaction is

• $\frac{1}{2}$

• $\frac{3}{4}$

• $\frac{3}{2}$

• $\frac{2}{3}$