Question

find the number of equivalents of HCL present in 100ml of its solution whose pH is 4

Answer 1

Explanation:

HCl is monobasic acid. Hence, its equivalent mass is equal to its molar mass and the number of equivalents are equal to the number of moles.

pH=−log[H

+

]=4

[H

+

]=10

−4

M

1 L of solution contains 10

−4

moles of hydrogen ions.

100 mL of solution (0.1 L) will contain 10

−4

×

1000

100

=10

−5

moles of hydrogen ions.

This is also equal to the number of equivalents of HCl present in 100 mL of solution of pH 4.