Question

What is molarity if naoh solution if 250ml of its contain 1mg of naoh

Answer 1

Molar mass of NaOH is 40 g/mol

40 gram of NaOH in 1L solution will make 1M solution.

So by unitary method:

10 gram of NaOH in 250 mL solution will make 1M solution.

1 gram=10^3 mg.

10 gram= 10^4 mg.

1 mg= 10 ^(-4) g.

Again by unitary method

10^(-4) g in 250mL solution will make 10^(-4) M solution or 0.0001 Msolution.

Answer 2

Explanation:

molar mass of of NaOH = 40g/mol

1 gram=10‐³ mg

Molarity =

$\frac{given \: mass \times 1000}{molar \: mass \: \times volume}$

$\frac{ {10}^{ - 3} \times {10}^{3} }{40 \times 250}$

${10}^{ - 3} \times {10}^{ - 1}$

${10}^{ - 4}$

M = ${10}^{ - 4}$