Phosphorus forms a number of oxoacids. Out of these oxoacids phosphinic acid has strong reducing property. Write its structure and also write a reaction showing its reducing behaviour .

Write a chemical reaction for its use of PCl3 as reducing agent.

Phosphorus forms a variety of oxyacids. In all these, phosphorus is sp^3 hybridised and is tetrahedrally bonded to four neighbouring atoms. These contain P-OH bonds, the hydrogen of which are ionisable giving acidic character to these compounds. These also contain P-H bonds in which hydrogens are notionisable because P and H have nearly same electronegativity. The presence of P-H group in these oxyacids is responsible for their reducing properties. The structures of some oxyacids are given below : Answer the following (1 to 7) questions : The oxyacid of P having tetrabasicity is

Explain Ostwald process for manufacturing nitric acid. Draw structure of nitric acid and write its uses also.

Write the expression which represent a perfect square number. Write its small perfect square number and also the greatest perfect square number have 3 digits.

Nitric acid forms an oxide of nitrogen on reaction with P_4O_10 . Write the reaction involved. Also write the resonating structures of the oxide of nitrogen formed.

Write the smallest five digit number and exress it in the form of its prime factors.

An element 'A' reacts with oxygen to form an oxide of the formula A_2O which dissolves in dil. HCl. The oxide formed turns red litmus paper blue. Write the formula of A_2O and its reaction with dil. HCl.