Question

1g ca was burnt in excess of o2 and the oxide was dissolved in water to make 1 litre of solution

Answer 1

when 1g ca was burnt in excess of o2 and the oxide was dissolved in water to make 1 litre of solution ------- answer is 0.05 N

Answer 2

Calicum combines with oxygen in the air to form Calcium oxide

$Ca + \frac{1}{2}O_2 \rightarrow CaO$

Calcium oxide on further treatment with water to form Calcium hydroxide

$CaO + H_2O \rightarrow Ca(OH)_2$

Atomic Weight of Ca = 40;  

Molecular weight of CaO = 40 + 16 = 56;

Molecular weight of $Ca(OH)_2$ = 40 + (2 x 17) = 40 + 34 = 74

We know that 40g of Calcium produces 74g of $Ca(OH)_2$

Therefore, 1g of Ca is equivalent to 74/40 g of $Ca(OH)_2$ = 1.85g

We know that the equivalent weight of $Ca(OH)_2$ is 37

Therefore, 1.85/37  = 0.05g equivalent of $Ca(OH)_2$  

Finally, if 0.05g is dissolved in 1L then we get 0.05N of $Ca(OH)_2$.