711.

What is the basicity of H₃PO₄?

Give reasons for the following observations:

It is necessary to remove CO when ammonia is prepared by Haber's process.

Account for the following:

(i) Acidic character increases from HF to HI.

(ii) There is a large difference between the melting and boiling points of oxygen and sulphur.

(iii) Nitrogen does not form pentahalide.

Draw the structures of the following :

 (i) ClF₃

 (ii) XeF4

(i) Which allotrope of phosphorus is more reactive and why?

(ii) How the supersonic jet aeroplanes are responsible for the depletion of ozone layers?

(iii) F₂ has lower bond dissociation enthalpy than Cl₂. Why?

(iv)  Which noble gas is used in filling balloons for meteorological observations?

 (v) Complete the equation: XeF2 + PF5 →

Complete the following chemical equations:

(i) Ca₃P₂ + H₂O -->

(ii) Cu + H₂SO₄(conc.)--> 

Arrange the following in the order of the property indicated by each set:

 
(i) HF, HCl, HBr, HI - increasing bond dissociation enthalpy.

(ii) H₂O, H₂S, H₂Se, H₂Te- increasing acidic character. 

Draw the structures of the following molecules:

(i) XeOF₄

(ii) H₂SO₄

Structural difference between White P and Red P:

Account for the following:

(i) PCl₅ is more covalent than PCl₃.

(ii) Iron on reaction with HCl forms FeCl₂  and not FeCl₃.