The chemical reaction 2O₃ $\to$3O₂ proceeds as :

(I) O₃ $\rightleftharpoons$ O₂ + O (fast)

(II) O + O₃ $\to$ 2O₂ (slow)

The rate expression should be :

• r = k[O₃]²

• r = k[O₃]² [O₂]^-1

• r = k[O₃] [O₂]

• None of these

For a 1^st order reaction if concentration is doubled then rate of reaction becomes

• doubles

• half

• four times

• remains same

The first order rate constant for dissociation of N₂O₅ is 6.2 x 10^-4 s^-1 .The half-life period (in s) of this dissociation will be :

• 1117.7

• 111.7

• 223.4

• 160.9

The IUPAC name of the compound :

 is :

• 2 - ethyl - 2 - methyl - 3 - hexanone

• 5 - ethyl - 5 - methyl - 4 - hexanone

• 5 , 5 - dimethyl - 4 - heptanone

• 3 , 3 - dimethyl - 4 - heptanone

The gas phase reaction of nitric oxide and bromine yields nitrosyl bromide :

2NO (g) + Br₂ (g) $\to$ 2NOBr (g)

The rate law is rate = k[NO]²[Br₂]

The overall reaction order is :

• 1

• 2

• 3

• 4

For a reaction X$\to$Y,the graph ofthe product concentration (x) versus time (t) came out to be a straight line passing through the origin. Hence the graph of $\frac{-\mathrm{d}\left[\mathrm{X}\right]}{\mathrm{dt}}$ and time would be

• straight line with a negative slope and an intercept on y-axis

• straight line with a positive slope and an intercept on y-axis

• a straight line parallel to x-axis

• a hyperbola.

If 8. 0 g of a radioactive isotope has a half-life of 10 yr .The half-life of 2.0 g of the same substance is :

• 2.5 yr

• 5 yr

• 20 yr

• lO yr

Which one of the following is a second order reaction ?

• H₂ + Br₂ $\to$ 2HBr

• NH₄NO₃ $\to$ N₂ + 3H₂O

• H₂ + Cl₂ $\stackrel{\mathrm{Sunlight}}{\to }$ 2HCl

• CH₃COOCH₃ + NaOH $\to$ CH₃COONa + CH₃OH

Assertion : Two different reactions can never have same rate of reaction.

Reason : Rate of reaction always depends only on frequency of collision and Arrhenius factor.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

Assertion : Rate of reaction of alkyl halide in Williamson's synthesis reaction is 1°RX > 2°RX > 3$°$RX.

Reason : It is a type of bimolecular substitution reaction (S_N2).

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false