31.

Which of the following is not a green house gas?

• Carbon dioxide

• Water vapour

• Methane

• Oxygen

Assertion : Solution of Na₂CrO₄ in water is coloured.

Reason : Oxidation state of Cr in Na₂CrO₄ is +6.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : PbI₄ is a stable compound.

Reason : Iodide stabilizes higher oxidation state.

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

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

• If assertion is true but reason is false

• If both assertion and reason are false.

Assertion : Haemoglobin is an oxygen carrier.

Reason : Oxygen binds as O₂^- to Fe of haemoglobin.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : Alkyl benzene is not prepared by Friedel-Crafts alkylation of benzene.

Reason : Alkyl halides are less reactive than acyl halides.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : Photochemical smog is produced by nitrogen oxides.

Reason : Vehicular pollution is a major source of nitrogen oxides.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : Increasing pressure on pure water decreases its freezing point.

Reason : Density of water is minimum at 273 K.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : The micelle formed by sodium stearate in water has - COO^- groups at the surface.

Reason : Surface tension of water is reduced by the addition of stearate.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : Cis-1,3-dihydroxycyclohexane exists in boat conformation.

Reason : In the chair form, there will not be hydrogen bonding between the two hydroxyl groups.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

The true statement for the acids of phosphorus, H₃PO₂, H₃PO₃ and H₃PO₄ is

• the order of their acidity is H₃PO₄ > H₃PO₃ > H₃PO₂

• all of them are reducing in nature

• all of them are tribasic acids

• the geometry of phosphorus is tetrahedral in all the three