Question

A substance of Ka of 1×10^-5 would be classified as a

Strong acid
Weak acid
Strong base
Weak base

Answer 1

A substance with a Ka of 1 x 10^-5 mol dm^-3 has a pKa of:
pKa = -logKa = 5
This is a relatively large pKa for an acid, so it is not very acidic, classifying it as a weak acid.
Hope this helps!

Answer 2

Answer: option B, weak acid

Explanation: Generally larger the ka , stronger the acid and its capability to release proton is more.

Or smaller the pka stronger the acid.

Here ka=1x10^-5 is too smaller value or pka=5 (pka=-logka) hence acts as week acid

Finally acidity is directly proportional to ka or inversely proportional to pka.