Question

a solution of NaoH contains 0.04 gm of NaoH per litre its pH is?

Answer 1

Moles = 0.04/40 = 0.001molarity = 0.001MNaOH ——> ( Na+). + (OH-)0.001...........0.001.....0.001pH = 14 - pOH pH =14 - (-log [OH-])pH= 14 + log 0.001pH = 14 + (-3) log 10pH = 14 - 3pH = 11

Answer 2

Answer: A solution of NaoH contains 0.04 gm of NaoH per litre its pH is 11.

Solution:

$Molarity=\frac{\text{given mass in grams}}{\text{molecular mass(g/mol)}\times \text{volume of solution(L)}}$

Molarity of NaOH = $\frac{0.04}{39.9\times 1L}=0.001 M$

Sodium hydroxide will fully dissociates in its aqueous solution.So the concentration of sodium ions are hydroxide ions will be same.

$[Na^+]=[OH^-]=0.001 M$

The pOH of the sodium solution:

$pOH=-log{[OH^-]}=-log{(0.001 M)}=3$

Since, pH+pOH = 14

The pH of the solution will be : 14 - 3 = 11