1

AIPMT 2012 Prelims

The protecting power of lyophilic colloidal sol is expressed in terms of
A
coagulation value
B
gold number
C
critical micelle concentration
D
oxidation number

Explanation

The lyophobic sols are less stable than lyophilic sols. The lyophilic sols are thus used to protect the lyophobic sols. This property of lyophilic sols is known as protective action of lyophilic sols.

Which can be represented by gold number. Lesser the gold number, higher is the protecting power.
2

AIPMT 2012 Prelims

Which one of the following statements is incorrect about enzyme catalysis?
A
Enzymes are mostly proteinous in nature.
B
Enzyme action is specific.
C
Enzymes are denatured by ultraviolet rays and at high temperature.
D
enzymes are least reactive at optimum temperature.

Explanation

Enzymes are most reactive at optimum temperature. The optimum temperature for enzyme activity lies between 40°C to 60°C.
3

AIPMT 2012 Prelims

In Freundlich adsorption isotherm, the value of 1/n is
A
between 0 and 1 in all cases
B
between 2 and 4 in all cases
C
1 in case of physical absorption
D
1 in case of chemisorption.

Explanation

${x \over m} = k.{p^{{1 \over n}}}$

Where ${x \over m}$ is the ratio of amount of adsorbent to the amount of adsorbate.

The value of n is always greater than 1. So, the value of ${{1 \over n}}$ lies between 0 and 1 in all cases.
4

AIPMT 2011 Prelims

If x is amount of adsorbate and m is amount of adsorbent, which of the following relations is not related to adsorption process?
A
x/m = $f$(p) at constant T
B
x/m = f(T) at constant p
C
p = f(T) at constant (x/m)
D
${x \over m} = p \times T$

Explanation

${x \over m} = p \times T$ is incorrect.