Question

How many grams naoh should be dissolved in 1 litre of solution to prepare a solution of ph =12?

Answer 1

Answer:

Amount of NaOH required to produce 1 litre of solution having 12 ph = 0.4 gram

Explanation:

As NaOH is a base so we find its POH

by the relation

$ph + poh = 14$

or

$poh = 14 - ph = 14 - 12 = 2$

where POH is the negative log of hydroxyl ion concentration:

POH = -log[OH] = 2

taking antilog on both sides, we have

[OH] = -antilog 2 = 1/100 = 0.01 mol

As one mole of NaOH = 40 gram yield one mole of [OH]

THUS to produce 0.01 mole of [OH] the amount of NaOH required would

= 40 × 0.01 = 4 gram