The pair whose both species are used in antiacid medicinal preparation is

• NaHCO₃ and Mg(OH)₂

• Na₂CO₃ and Ca(HCO₃)₂

• Ca(HCO₃)₂ and Mg(OH)₂

• Ca(OH)₂ and NaHCO₃.

Which of the following is a false statement ?

• Fluorine is more electronegative than chlorine

• Nitrogen has greater IE₁ than oxygen

• Lithium is amphoteric

• Chlorine is an oxidising agent

Which of the following is a use of alum ?

• Making explosives

• Bleaching clothes

• Water softening

• All of the above

The pair of amphoteric hydroxides is

• Al(OH)₃, LiOH

• Be(OH)₂, Mg(OH)₂

• B(OH)₃, Be(OH)₂

• Be(OH)₂, Zn(OH)₂

Which of the following is only acidic nature?

• Be(OH)₂

• Mg(OH)₂

• B(OH)₃

• Al(OH)₃

The molecular formula of 'salt petre' is :

• KNO₃

• NaNO₃

• NaCl

• Na₂SO₄

On dissolving moderate amount of sodium metal in liquid NH₃ at low temperature, which one of the following does not occur?

• Blue coloured solution is obtained.

• Na⁺ ions are formed in the solution.

• Liquid NH₃ becomes good conductor of electricity

• Liquid ammonia remains diamagnetic

Which of the following reaction produces hydrogen ?

• Mg + H₂O

• H₂S₂O₈ + H₂O

• BaO₂ + HCl

• Na₂O₂ + 2HCl

439.

Assertion: Mg is not present in enamel of human teeth.

Reason : Mg is an essential element for biological functions of human.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

Match the flame colours of the alkaline earth metal salts in the Bunsen burner.

A. Calcium	p. Brick red
B. Strontium	q. Apple green
C. Barium	r. Crimson

• A - p; B - r; C - q

• A - r; B - p; C - q

• A - q; B - r; C - p

• A - p; B - q; C - r