231.

For a chemical reaction, mA → xB, the rate law is r = k[A]². If the concentration of A is doubled, the reaction rate will be

• doubled

• quadrupled

• increases by 8 times

• unchanged

For 3A → 2B, rate of reaction, +$\frac{\mathrm{d}\left[\mathrm{B}\right]}{\mathrm{dt}}$ is equal to

• $-\frac{3}{2}\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}$

• $-\frac{2}{3}\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}$

• $+2\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}$

• $-\frac{1}{3}\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}$

The activation energy of a chemical reaction can be determined by,

• evaluating rate constants at two different temperatures

• changing the concentration of reactants

• evaluating the concentration of reactants at two different temperatures

• evaluating rate constant at standard temperature

Reactions in zeolite catalyst depend on

• pores

• apertures

• size ofcavity

• All of the above

Which of the following statement is incorrect?

• The rate of law for any reaction cannot be determined experimentally

• Complex reactions have fractional order

• Biomolecular reactions involved simultaneous collision between two species

• Molecularity is only applicable for elementary reaction

Which of the following statement is in accordance with the Arrhenius equations?

• Rate of reaction does not change with increase in activation energy

• Rate constant decreases exponentially with increase in temperature

• Rate of a reaction increases with increases in temperature and decreases in activation energy

• none of these

The minimum energy required forthe reacting molecules to undergo reaction is :

• potential energy

• kinetic energy

• thermal energy

• activation energy

The rate constant of a first order reaction is 6.9 × 10^-3 s^-1. How much time will it take to reduce the initial concentration to its 1/8 th value?

• 100 s

• 200 s

• 300 s

• 400 s

For a reaction 1/2 A→ 2B rate of disapperance of A is related to rate of appearance of B by the expression.

• $-\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}= \frac{1}{2}\frac{\mathrm{d}\left[\mathrm{B}\right]}{\mathrm{dt}}$

• $-\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}= 4\frac{\mathrm{d}\left[\mathrm{B}\right]}{\mathrm{dt}}$

• $-\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}= \frac{\mathrm{d}\left[\mathrm{B}\right]}{\mathrm{dt}}$

• $-\frac{\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}= \frac{1}{4}\frac{\mathrm{d}\left[\mathrm{B}\right]}{\mathrm{dt}}$

In a 1^st order reaction, reactant concentration C varies with time t as :

• 1/C increases linearly with t

• log C decreases linearly with t

• C decreases with 1/ t

• log C decreases with 1/ t