The following data is obtained during the first order thermal decomposition of 2A(g)→ B(g) +C(s) at constant volume and temperature.

S.No	Time	Total pressure in Pascal
1.	At the end of 10 min	300
2.	After completion	200

The rate constant in min^-1

• 0.0693

• 6.93

• 0.00693

• 69.3

For a reaction, A + B → products, the rate of the reaction at various concentrations are given below

Expt no.	[A]	[B]	Rate (mol dm-3 s-1)
1.	0.2	0.2	2
2.	0.2	0.4	4
3.	0.6	0.4	36

The rate law for the above reaction is

• r = k[A][B]²

• r = k [A]³[B]

• r = k [A]²[B]²

• r = k [A]²[B]

The rate of reaction increases with rise in temperature because of

• onl increase in number of activated molecules

• Increase in energy of activation

• decrease in energy of activation , increase in number activated molecules and also the number of effective collisions increase.

• only increase in the number of effective collisions

A first order reaction is 60% complete in 20 minutes. How long will the reaction take to be 84% complete?

• 68 min

• 40 min

• 76 min

• 54 min

If 50% of the reactant is converted into a product in a first order reaction in 25min, how much of it would react in 100min?

• 93.75%

• 87.5%

• 75%

• 100%

Temperature coefficient of a reaction is 2. When temperature is increased from 30°C to 90°C, the rate of reaction is increased by

• 60 times

• 64 times

• 150 times

• 400 times

A (g) $\stackrel{∆}{\to }$ P (g) + Q (g) + R (g), follows first order kinetics with a half-life of 69.3 s at 500°C. Starting from the gas 'A' enclosed in a container at 500°C and at a pressure of 0.4 atm, the total pressure of the system after 230 s will be

• 1.15 atm

• 1.32 atm

• 1.22 atm

• 1.12 atm

In a first order reaction, the concentration of the reactant is reduced to 12.5% in 1hr. When was it half completed?

• 3hr

• 20min

• 30min

• 15min

The half-life period of a first order reaction is 60 min. What percentage will be left over after 240 min?

• 6.25%

• 4.25%

• 5%

• 6%

230.

Half-life period of a first order reaction is 10 min. Starting with initial concentration 12 M, the rate after 20 min is

• 0.0693 M min^-1

• 0.693 × 3M min^-1

• 0.0693  × 3M min^-1

•  0.0493 × 4M min^-1