Identify the correct acid and conjugate base pair in this equation: HNO2 + HS - - -> NO2 - + H2S

Acid: HNO₂

Conjugate base: NO₂⁻

Base: HS⁻

Conjugate acid: H₂S

Explanation:

HNO₂ + HS⁻ → NO₂⁻ + H₂S

This is the reaction of nitrous acid with hydrosulfide, to generate nitrite and sulfide acid.

HNO₂ is a weak acid that release the proton to the HS⁻, so the HS⁻ is the base.

Proton that is caught by the HS⁻, produce the H₂S so, if the HS⁻ is the base (accepts a proton from other compound), the H₂S acts like the conjugate acid.

In nitrous acid, which is behaving as an acid (a weak one), the nitrite becomes in the conjugate strong base.

HNO2 is the acid

NO2 - is the conjugate base

Explanation:

In an acid base rxn, the proton donor is the acid while the proton receptor is the base. Same goes for conjugate acid and conjugate base.