Test: Surface Chemistry - Chemistry MCQ

The extent of adsorption increases with increase in polarity and molar mass so the correct option is b.

Nitrocellulose when dissolved in 4% alcohol-ether mixture is called collodion

It is due to weak van der Waals’ forces of attraction.

∵ Lesser the coagulation value, more is coagulating power meaning it is inversely proportional.

To find the amount of acetic acid adsorbed per gram of charcoal, we need to calculate the mass of acetic acid adsorbed by the activated charcoal and divide it by the mass of charcoal used.

The initial concentration of acetic acid is 0.06 M, and after adsorption, the final concentration is 0.042 M. The difference between the initial and final concentrations represents the amount of acetic acid adsorbed by the activated charcoal.

0.06 M - 0.042 M = 0.018 M

Now we need to find the mass of acetic acid (in grams) that was adsorbed by the activated charcoal. We can use the equation: molarity x volume = moles

0.018 M x 50 ml = 0.9 moles

Now, we can find mass of acetic acid adsorbed by mass = moles x molar mass

mass = 0.9 moles x 60 g/mol = 54 g

Now we need to divide the mass of acetic acid adsorbed by the mass of activated charcoal used:

54 g / 3 g = 18 g/g

Therefore, the amount of acetic acid adsorbed per gram of charcoal is 18 mg, So the correct answer is 2.

• It is called selectivity of catalyst as per requirement.
• Catalyst changes only the EA (Activation energy) of the reaction.

2AuCl₃ + 3HCHO + 3H₂O → 2Au + 3HCOOH + 6HCl

xm = k C1/n [where ‘C’ is concentration of solution]

The absorption of a gas on a surface is significantly influenced by its critical temperature. When the critical temperature of a gas is higher, there is an enhanced capacity for absorption on the surface of any material. Conversely, lower critical temperatures lead to reduced absorption on the surface. This phenomenon is attributed to the increased attractive forces between the surface and the gaseous molecules at higher critical temperatures. Referring to the provided table, it is evident that hydrogen gas exhibits the lowest critical temperature, making it the least absorbed gas.

The temperature above which micelles formation takes place is called Kraft temperature.

Gold number is used to measure protective power of colloids. If the gold number is lowered, the protective power will increase, e.g., gelatin.

• All are correct
• That is correct at low pressure,
• That is correct at moderate pressure and
• That is correct at high pressure (saturation pressure).

ΔG < 0 means process is spontaneous because adsorption is exothermic in nature, ΔH = negative and entropy is decreasing, i.e., ΔS will come out as negative.

Low temperature and high pressure provide help in increased physical adsorption because van der Waals’ forces of attraction will increase.

same charge on particles causes repulsion which further allows particles to settle down.

When both the processes of adsorption and absorption take place, it is called sorption, e.g., dying of cotton fiber.

At high temperature, covalent bonds will be seen forming as activation energy will be provided.

(a) and (c) are correct, when n = 0.
∴ xm vs p graph is line parallel to x-axis.
when 1n = 0, xm is independent of pressure at high pressure.

PO₃⁻⁴ works in most effective way for positively charged Fe(OH)₃sol due to higher charge.