Question

volume of 18M H2SO, taken for preparing 0.5M H2SO4(100 ml solution)

Answer 1

This is like dilution.

We take an acid of high molarity then we dilute it to get low molarity.

The formula that helps in solving this problem is:

m1v1 = m2v2

Where:
m1 = initial molarity = 18M
v1 = this is the initial volume (it is what is required)
m2 = final molarity = 0.5M
v2 = final volume = 100ml = 100/1000 = 0.1 litre

therefore;

18v1 = 0.5x0.1

v1 = (0.5x0.1)/18 
     = 0.00278 litres
     = 2.78 ml

So, in preparing 100ml of 0.5M acid solution, we take 2.78ml of the 18M acid