A substance that gives a brick red flame and breaks down on heating giving oxygen and a brown gas is-

1. Calcium carbonate.

2. Magnesium carbonate.

3. Magnesium nitrate.

4. Calcium nitrate.

A: Alkali metals can be extracted by chemical reduction

R: Alkali metals are weak reductants.

1. Both Assertion & Reason are true and the reason is the correct explanation of the assertion.

2. Both Assertion & Reason are true but the reason is not the correct explanation of the assertion.

3. Assertion is a true statement but Reason is false.

4. Both Assertion and Reason are false statements.

All group-2 metals dissolve in liquid ammonia to produce a bright blue colour. The colour is due to-

1. A change in the structure of ammonia.

2. d-d transition.

3. The spectrum of the solvated electrons.

4. An electronic transition from a lower to a higher energy state.

The fire extinguisher contains NaHCO₃ and the compound (X). The compound (X) maybe -

1. CH₃COOH

2. NaOH

3. C₆H₅OH

4. None of the above. 

Gypsum on heating can change to :

1. Orthorhombic form.

2. Plaster of paris.

3. Dead plaster.

4. All of the above.

$∆{\mathrm{H}}_{\mathrm{solution}}$ is positive for

I. LiF

II. CsI

III. RbF

IV. KF

(1) I, II, III & IV

(2) II only

(3) I only

(4) I & II only

The cation of alkali metals are found as M(H₂O)⁺_n in H₂O.

The value of 'n' is maximum for -

1. Na⁺

2. K⁺

3. Rb⁺

4. Li⁺

${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ on heating (below 200 degrees celsius) liberates a gas. The same gas will be obtained below 600 degrees celsius by :

1. Heating ${\mathrm{NH}}_4{\mathrm{NO}}_2$

2. Heating ${\mathrm{NH}}_4{\mathrm{NO}}_3$

3. Heating ${\mathrm{Mg}}_3{\mathrm{N}}_2$

4. None of the above

The incorrect statement among the following is : 

1. The atomic radius of Na is greater than that of Mg.

2. Density of K is more than Na.

3. Melting point & boiling point of Ca are greater than those of Mg.

4. Mg does not react with cold water.

A Brine solution on electrolysis will not give : 

1.  NaOH

2.  ${\mathrm{Cl}}_2$

3.  ${\mathrm{H}}_2$

4.  ${\mathrm{O}}_2$