22437.The extent of adsorption of a gas on a solid depends on ______.
temperature of the gas
pressure of the gas
nature of the gas
all are correct
22438.Among the electrolytes Na2SO4, CaCl2, Al2(SO4)3 and NH4Cl, the most effective coagulating agent for Sb2S3 sol is
Na2SO4
CaCl2
Al2(SO4)3
NH4Cl
22439.Identify the correct statement regarding enzymes:
Enzymes are specific biological catalysts that cannot be poisoned.
Enzymes are normally heterogeneous catalysts that are very specific in action
Enzymes are specific biological catalysts that can normally function at very high temperature (T – 1000K).
Enzymes are specific biological catalysts that possess well defined active sites.
22440.Which of the following statements is correct for the spontaneous adsorption of a gas?
ΔS is negative therefore, ΔH should be highly positive
ΔS is negative therefore, ΔH should be highly negative
ΔS is positive therefore, ΔH should be negative
ΔS is positive therefore, ΔH should also be highly positive
22441.Alum helps in purifying water by
coagulating the mud particles
sulphate part which combines with dirt and removes it
forming Si complex with clay particles
making mud water soluble
22442.Which type of colloid is the dissolution of sulphur (S8)?
Associated colloid
Micelle
Multimolecular colloid
Macromolecular colloid
22443.Volume of a colloidal particle, Vc as compared to the volume of a solute particle in a true solution, Vs could be
$\dfrac{\text{V}_\text{c}}{\text{V}_\text{s}} \approx 1$
$\dfrac{\text{V}_\text{c}}{\text{V}_\text{s}} \approx 10^{–3}$
$\dfrac{\text{V}_\text{c}}{\text{V}_\text{s}} \approx 10^{3}$
$\dfrac{\text{V}_\text{c}}{\text{V}_\text{s}} \approx 10^{23}$
22444.Which of the following characteristics is not correct for physical adsorption?
Adsorption on solid is reversible.
Adsorption is spontaneous.
Adsorption increases with increase in temperature.
Both enthalpy and entropy of adsorption are negative.
22445.Which of the following statement about the zeolites is false?
They have open structure which enables them to take up small molecules.
Zeolites are aluminosilicates having three dimensional network.
Some of the SiO–4
4 units are replaced by AlO–5
4 and AlO–9
6 ion in zeolites.
4 units are replaced by AlO–5
4 and AlO–9
6 ion in zeolites.
They are used as cation exchangers
22446.The colour of sky is due to
absorption of light by atmospheric gases
wavelength of scattered light
transmission of light
All of these
22447.Which one of the followings forms micelles in aqueous solution above certain concentration?
Dodecyl trimethyl ammonium chloride
Glucose
Urea
Pyridinium chloride
22449.Sulphur sol contains
Discrete S – atoms
Discrete S – molecules
Large aggregates of S – molecules
Water dispersed in Solid Sulphur
22450.The dispersed phase and dispersion medium of fog respectively are
solid, liquid
liquid, liquid
liquid, gas
gas, liquid
22451.Which property of colloidal solution is independent of charge on the colloidal particles?
Coagulation
Electrophoresis
Electro–osmosis
Tyndall effect
22452.Which of the following colloids cannot be easily coagulated?
Lyophobic colloids
Multimolecular colloids
Macromolecular colloids
Irreversible colloids
22453.3 g of activated charcoal was added to 50 mL of acetic acid solution (0.06 N) in a flask. After an hour it was filtered and the strength of the filtrate was found to be 0.042 N. The amount of acetic acid adsorbed (per gram of charcoal) is
18 mg
36 mg
42 mg
54 mg
22454.According to adsorption theory of catalysis, the speed of the reaction increases because:
adsorption produces heat which increases the speed of the reaction.
in the process of adsorption, the activation energy of the molecules becomes large.
the concentration of the reactant molecules at the active centres of the catalyst becomes high due to adsorption.
adsorption lowers the activation energy of the reaction.