Question

A sample of h2so4 (density 1.8 gm/ml) is 90% by weight. What is the volume of acid
that has to be used to make 1L of 0.2M h2so4?

Answer 1

Answer: 12•1 ml

Explanation:

We know that

Molarity= no. of mol/vol. in L

no. of mol = Molarity× vol. in L

no. of mol required= 0•2 × 1

=0•2 mol

Since % by weight= 90%

→ 100g sol. = 90g H²SO⁴

since vol.=mass/ density

→ 100/18 ml = 90g H²SO⁴

no of mol = given mass/ molar mass

= 90/98mol

→ 90/98 mol = 100/18 ml

Since we require 0.2 mol

On using unitary method,

required vol. 12•1 ml

Answer 2

Answer:12.09

Explanation:by using the formula

Molarity=percentage ×density×10÷molecular mass

M=90×1.8×10÷98

    =16.53

Now,

        M1V1=M2V2

  That is,

         16.53*x=0.2×1000

By solving this,

           X=12.09mL