In the following reactions, ZnO is respectively acting as a/an :

(a) ZnO + Na₂O $$\to$$ Na₂ZnO₂

(b) ZnO + CO₂ $$\to$$ ZnCO₃

pK_a of a weak acid (HA) and pK_b of a weak base (BOH) are 3.2 and 3.4, respectively. The pH of their salt (AB) solution is :

Which of the following compounds will behave as a reducing sugar in an aqueous KOH solution?

The most abundant elements by mass in the body of a healthy human adult are: Oxygen (61.4%); Carbon (22.9%), Hydrogen (10.0%); and Nitrogen (2.6%). The weight which a 75 kg person would gain if all ¹H atoms are replaced by ²H atoms is: