Question

How much water is to be added to dilute 10ml of 10 NHcl to make it decinormal

Answer 1

N1VI=N2V2
10*10=0.1v
v=1000 ml
therefore 990 ml of water 

Answer 2

Answer: 990 ml

Explanation: The number of gram equivalents remain same.

$N_1V_1=N_2V_2$

where,

$N_1$  = concentrations  of first solution= 10N

$N_2$  = concentrations  of second solution=$\frac{1}{10}=0.1N$

$V_1$ = volume of first solution= 10 ml

$V_2$ = volume of second solution = ?

$10N\times 10ml=0.1N\times V_2$

$V_2$ = 1000 ml.

Thus we need to add (1000-10)=990 ml of water to get decinormal solution.