Question

What will be the pH value of $0.02M$${H_2}S{O_4}$solution.
A.$1.7$
B.$1.4$
C.$2$
D.$4$

Answer 1

Hint: pH value is used to determine the acid or basic nature. For example: if pH value ranges from $0 - 7$ then it will be acidic in nature and if its value ranges from $7 - 14$ then it will be basic in nature.

Complete step by step answer:
pH values: The values used to determine the acidic or basic nature of solutions, are known as pH values. For example: if pH value ranges from $0 - 7$ then it will be acidic in nature and if its value ranges from $7 - 14$ then it will be basic in nature. If the pH value for any solution comes out to be $7$ then it will be treated as a neutral solution.
Acidic solution: The solutions which are acidic in nature, are known as acidic solutions. The pH values range from $0 - 7$.
Basic solution: The solutions which are basic in nature, are known as basic solutions. The pH values range from $7 - 14$.
Neutral solution: The solutions which are neither acidic nor basic in nature, are known as neutral solutions. The pH value for neutral solution is $7$.
How to calculate pH value of a solution:
The formula which is used to calculate the pH value of the solution is as $pH = - \log [{H^ + }]$ i.e. pH is defined as the negative logarithm of the concentration of hydrogen ion.
Now if we want to calculate the pH for sulphuric acid i.e. ${H_2}S{O_4}$, then it will be calculated as:
First of all we need to calculate the hydrogen ion concentration. We know that one mole of sulphuric acid will give two moles of hydrogen ion. ${H_2}S{O_4} \to 2{H^ + } + S{O_4}^{2 - }$
So, $0.02M$ sulphuric acid will give $0.04M$ hydrogen ions.
Now, put the value of hydrogen ion concentration value in the pH value formula, then we will get pH as: $pH = - \log [0.04] = 1.4$
So pH will be $1.4$.
Hence, the correct answer is option B.

Note:
If by the question we are unable to get the concentration of hydrogen ion but we are getting the concentration of hydroxide ion then we can use the formula as $pH = - \log [O{H^ - }]$ and then $pH + pOH = 14$. This will give you the value of pH.