4NA Sc(Chem) Bridging 2024

Y + metal carbonate → salt + carbon dioxide + water

What is Y?

• carbon

• acid

• metal

• alkali

A sample of magnesium is added to dilute nitric acid in a test tube.

Effervescence is observed and magnesium nitrate solution is formed.

What other products are formed?

• water only

• hydrogen only

• carbon dioxide and water

• ammonia only

What is the test to identify hydrogen gas?

• Moist red litmus paper turns blue.

• Lighted splint extinguishes with a 'pop' sound.

• White precipitate forms in limewater.

• Glowing splint relights.

When magnesium reacts with hydrochloric acid, magnesium chloride and hydrogen are formed.

What is the chemical formula of magnesium chloride?

• Mg

• MgCl

• MgCl₂

• H₂

What is the correct formula of calcium nitrate?

Note: calcium ion is Ca²⁺, nitrate ion is NO₃^-

• CaNO₃

• Ca₂NO₃

• Ca(NO₃)₂

• Ca₂(NO₃)₂

What is an alkali?

• a substance that produces H⁺ ions in aqueous solution

• a substance that produces OH^- ions in aqueous solution

• a substance that produces O^2- ions in aqueous solution

Which substance is an alkali which produces OH^- ions in aqueous solution?

• potassium hydroxide

• sulfuric acid

• aluminium oxide

• magnesium

potassium hydroxide  +  ammonium chloride  →  Q  +  water  +  ammonia

What is salt Q?

• sodium chloride

• sodium nitrate

• potassium chloride

• potassium nitrate

Which are the 3 amphoteric oxides?

Recall: amphoteric oxides react with both acids and bases.

• zinc oxide

• calcium oxide

• aluminium oxide

• lead(II) oxide