Question

The volume of water added to 500 ml 0.5 M NaOH solution so that its strength become 10mg NaOH per ml

Answer 1

your answer is ready here

Answer 2

Answer: 500 ml

Explanation: $Strength=Molarity\times Molar mass$

Given: Strength of $NaOH$= 10 mg/ml = 10 g/l

Thus $10g/l=Molarity\times 40g/mol$

Molarity of $NaOH$=0.25M

Now using Molarity equation:

$M_1V_1=M_2V_2$

where $M_1$ = Molarity of first solution

$V_1$ = Volume of first solution

$M_2$= Molarity of second solution

$V_2$  = Volume of second solution

$0.5M\times 500ml=0.25\times V_2ml$$V_2=1000ml$

Thus to 500 ml of first solution, 500 ml of water needs to be added to make the volume 1000 ml.