Acids, bases and salts

Front

After a compound X was added to water, the pH using indicator paper was less than 7. The resulting solution was added to some calcium carbonate and it was noted that effervescence took place. What could compound X be? Options: HNO₃, MgO, Na₂O, CaO

Back

HNO₃

Front

A solution was added to some ammonium chloride then heated. A gas with a pungent smell that turned moist red litmus blue was produced. What could have been present in the original solution?

Back

potassium hydroxide

Front

What is the best sequence for synthesizing lead iodide from the following steps? 1. Mix lead nitrate and potassium iodide 2. Dry 3. Filter 4. Mix lead sulphate and potassium iodide

Back

1, 3, 2

Front

A salt was being prepared by adding an acid to a carbonate. However, after a while, the reaction ceased and a precipitate began to form without all of the carbonate reacting. Which of the following pairs of acid and carbonate? Options: CaCO₃, H₂SO₄; CuCO₃, HCl; BaCO₃, HNO₃; Na₂CO₃, H₂SO₄

Back

CaCO₃, H₂SO₄

Front

Sodium hydroxide was added to a solution and it was noticed that a white precipitate was formed at first then dissolved in excess. On adding aqueous ammonia to a fresh sample of the solution, a white precipitate was formed which did not dissolve in excess. Which ion could have been present in the solution? Options: Fe²⁺, Al³⁺, Zn²⁺ , Ca²⁺

Back

Al³⁺

Front

What is the best way of making zinc carbonate?

Back

Shake solid zinc sulphate with water and add aqueous sodium carbonate

Front

What is the best description of a salt?

Back

Forms when all or part of the hydrogen ions in an acid is replaced

Front

A lighted splint was held over a flask in which a gas was given off. The splint went out with a pop. Which gas was given off?

Back

hydrogen

Front

What is an example of an amphoteric oxide?

Back

aluminium oxide