Question

How many moles of NaOH are present in 3L of water, if pH of solution is 10

Answer 1

Answer:

As we know that, no. of moles = Wt.Mol. wt. Mol. wt. of NaOH = 40 g Wt. of NaOH = 2 g (Given) Therefore,No. of mles = 240 = 0.05 mol As we know that molarity ... More

Answer 2

Given:

The volume of solution, V = 3 L

The pH of solution = 10

To Find:

The no of  moles of NaOH present in the given volume of solution.

Calculation:

- We know that:

pH + pOH = 14

⇒ 10 + pOH = 14

⇒ pOH = 4

- Now, pOH = -log[OH⁻]

⇒ 4 = -log[OH⁻]

⇒ [OH⁻] = 10⁻⁴ M

- So, the molarity of NaOH is 10⁻⁴ M.

- No of moles of NaOH = Volume × Molarity

⇒ n = 3 × 10⁻⁴

- So, the no of moles of NaOH present in 3 L of water is 3 × 10⁻⁴.