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%

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

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

539.

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