List-I (Sol) | List-II (Method of preparation) |
---|---|
A) \( \text{As}_2\text{S}_3 \) | I) Bredig's arc method |
B) \( \text{Au} \) | II) Oxidation |
C) \( \text{S} \) | III) Hydrolysis |
D) \( \text{Fe(OH)}_3 \) | IV) Double decomposition |
A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)):
A wooden block of mass M lies on a rough floor. Another wooden block of the same mass is hanging from the point O through strings as shown in the figure. To achieve equilibrium, the coefficient of static friction between the block on the floor and the floor itself is
The study of the chemical phenomena that occur at the interface of two surfaces which can be solid-liquid, solid-gas, solid-vacuum, liquid-gas, etc.
Read Also: Surface Chemistry
Applications of surface chemistry are:
The process of attraction and aggregation of the molecules of a substance on the surface of a solid is known as adsorption. For Example, N2 adsorbs on the surface of activated charcoal
Two types of adsorption are:-
The process through which the refined metals convert themselves into more stable compounds is known as corrosion.
The type of technique used in order to purify the substances to separate Solids from liquids is known as crystallisation.
The process wherein a catalyst is used in order to increase the rate of a chemical reaction is known as catalysis. The catalyst does not undergo any transformation and can be recovered in a chemically unchanged state.
There are two types of catalysis:-