Chemistry:2013:CBSE:[ All India]:Set-I

Chemisorption has a higher enthalpy of adsorption.

Electrolytic refining is used for the refining of copper metal.

Mustard gas and phosgene gas are the poisonous gases that can be prepared from the chlorine gas.

The increasing order of the boiling points is:

On hydrolysis, sucrose gives an equimolar mixture of D-(+)-glucose and D-(–)-fructose.

The repeating structural unit of the given polymer contains only one type of monomer unit, i.e. vinyl chloride, CH₂=CH–Cl, therefore, it is a homopolymer.

(i) In the Schottky defect, the equal number of positive and negative ions is missing from the ionic crystal. As a result of this defect, the number of ions decreases. Due to this, the mass decreases whereas the volume remains the same. Hence, the density of the solid decreases.

(ii) When silicon is doped with P (group 15 element), the silicon atoms at some lattice sites are substituted by the atoms of P. Now, as these atoms have five valance electrons, after forming the four covalent bonds with the neighbouring silicon atoms, the fifth extra electron is free and gets delocalised. These delocalised electrons increase the conductivity of the silicon.