Question

A chemist dissolves of pure nitric acid in enough water to make up of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

Answer 1

The given question is incomplete. The complete question is

A chemist dissolves 314 mg of pure nitric acid in enough water to make up 190 ml of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

Answer:  

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute= $\frac{\text{Given mass}}{\text{Molar mass}}=\frac{0.314g}{63g/mol}=4.98\times 10^{-3}moles$

$V_s$ = volume of solution in ml = 190 ml

$Molarity=\frac{4.98\times 10^{-3}\times 1000}{190}=0.026M$

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.

1 mole of $HNO_3$ gives 1 mole of $H^+$

Thus 0.026 moles of $HNO_3$ give= $\frac{1}{1}\times 0.026=0.026moles$ of $H^+$

$pH=-\log [H^+]$

Putting in the values:

$pH=-\log[0.026]=1.58$

Thus pH of the solution is 1.58