Question

What is the pH of a 0.0042 M hydrochloric acid solution?

A) 5.47
B) 11.62
C) 7.00
D) 8.53
E) 2.38

Answer 1

E) 2.38

Step-by-step explanation:

The pH of any solution , helps to determine the acidic strength of the solution ,

i.e. ,

• Lower the value of pH , higher is its acidic strength

and ,

• Higher the value of pH , lower is its acidic strength .

pH is given as the negative log of the concentration of H⁺ ions ,

hence ,

pH = - log H⁺

From the question ,

the concentration of the solution is 0.0042 M , and being it a strong acid , dissociates completely to its respective ions ,

Therefore , the concentration of H⁺ = 0.0042 M .

Hence , using the above equation , the value of pH can be calculated as follows -

pH = - log H⁺

pH = - log ( 0.0042 M )

pH = 2.38 .