Chemistry
Assertion (A): Zinc oxide reacts with acids as well as bases to form salt and water.
Reason (R): Zinc oxide is amphoteric in nature.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
Both A and R are true and R is the correct explanation of A.
Explanation — Zinc oxide reacts with both acids and concentrated alkalis (NaOH and KOH) forming salt and water.
ZnO + 2HCl ⟶ ZnCl2 + H2O
ZnO + 2NaOH ⟶ Na2ZnO2 + H2O
Hence the assertion (a) is true.
Reason (R) is true because zinc oxide is amphoteric in nature, reacts with both acids and concentrated alkalis forming salt and water. Hence Both A and R are true and reason (R) is the correct explanation of assertion(A).
Related Questions
Assertion (A): Hydrogen gas is liberated when metals like Zn, Al, Pb react with caustic alkalies.
Reason (R): Alkalies are soluble in water.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Oxides of most of the metals are basic in nature.
Reason (R): All metal oxides dissolve in water forming alkalis.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Fill in the blanks sentence case:
(a) …………… (AgCl/PbCl2) is a white precipitate soluble in excess of NH4OH.
(b) Addition of sodium hydroxide solution to ferrous sulphate solution produces a …………… (green/reddish brown) precipitate which is …………… (soluble/insoluble) in excess of NaOH solution.
(c) Ammonium chloride and sodium chloride can be distinguished by heating them with an …………… (acid/alkali).
(d) Element …………… (Fe/Zn/Cu) produces hydrogen by reacting with both acid as well as alkali.
Match the following:
Sodium hydroxide / Ammonium hydroxide solution is added to the solutions containing the ions mentioned in column 1. Match them to the colours of their precipitates in column 2.
Column 1 Column 2 (a) Pb2+ (i) Blue ppt. (b) Fe2+ (ii) Reddish brown ppt. (c) Zn2+ (iii) Dirty green ppt. (d) Fe3+ (iv) Gelatinous white ppt. soluble in excess NaOH (e) Cu2+ (v) White ppt. soluble in excess NH4OH