Answer:
Explanation:
pH = 4.55
[ H⁺ ] = 10⁻⁴°⁵⁵
= 2.82 x 10⁻⁵
Let the acid be HA and its molar concentration be a .
HA ⇄ H ⁺ + A ⁻
a - .094x10⁻³a .094x10⁻³a .094x10⁻³a
.094x10⁻³a = 2.82 x 10⁻⁵
a = 30 x 10⁻²
= .3
a - .094x10⁻³a = .3 - .094 x 10⁻³ x .3
= .29997 approx
Ka = 2.82 x 10⁻⁵ x 2.82 x 10⁻⁵ / .29997
= 7.95 x10⁻¹⁰ / .29997
= 26.5 x 10⁻¹⁰
= 27 x 10⁻¹⁰ ( rounding off to two digits )
