The rate of a chemical reaction doubles for every 10ºC rise of temperature. If the temperature is raised by 50ºC, the rate of the reaction increases by about

• 10 times

• 24 times

• 32 times

• 32 times

The time for half life period of a certain reaction A → Products is 1 hour. When the initial concentration of the reactant ‘A’ is 2.0 mol L^–1, how much time does it take for its concentration to come from 0.50 to 0.25 mol L^–1 if it is a zero order reaction?

• 1 h 

• 4 h 

• 0.25 h 

• 0.25 h 

Two reactions R₁ and R₂ have identical pre-exponential factors. Activation energy of R₁ exceeds that of R₂ by 10 kJ mol^–1. If k₁ and k₂ are rate constants for reactions R₁ and R₂ respectively at 300 K, then ln(k₂/k₁) is equal to-
(R = 8.314 J mol^–1K^–1)

• 8

• 12

• 6

• 6

The half life period of a first order chemical reaction is 6.93 minutes. The time required for the completion of 99% of the chemical reaction will be (log 2=0.301) 

• 230.3 minutes

• 23.03 minutes

• 46.06 minutes

• 46.06 minutes

Solid Ba (NO₃)₂ is gradually dissolved in a 1.0x 10⁻⁴ × Na₂CO₃ solution. At what concentration of Ba²⁺ will a precipitate begin to form?(K_sp for BaCO₃ = 5.1 ×10⁻⁹  )

• 4.1 x 10^-5 M

• 5.1 x 10^-5 M

• 8.1 x 10^-8 M

• 8.1 x 10^-8 M

For a reaction 1/2A →2B, rate of disappearance of ‘A’ is related to the rate of appearance of ‘B’ by the expression

The energies of activation for forward and reverse reactions for A₂ + B₂ ⇌ 2AB are 180 kJ mol^–1 and 200 kJ mol^–1 respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol^–1. The enthalpy change of the reaction (A₂ + B₂ → 2AB) in the
presence of catalyst will be (in kJ mol^–1) –

• 300

• 120

• 280

• 280

Consider the reaction, 2A + B → Products. When the concentration of B alone was doubled, the half-life did not change. When the concentration of An alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is –

• L mol^–1 s^–1

• no unit

• mol L^–1s^–1

• mol L^–1s^–1

A radioactive element gets spilled over the floor of a room. Its half-life period is 30 days. If the initial activity is ten times the permissible value, after how many days will it be safe to enter the room ?

• 1000 days

• 300 days

• 50 days

• 50 days

320.

Which of the following nuclear reactions will generate an isotope?

• neutron particle emission

• positron emission

• α-particle emission

• α-particle emission