In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to

• generate heat

• create potential difference between the two electrodes

• produce high purity water

• remove adsorbed oxygen from electrode surfaces

Amongst the following compounds, the optically active alkane having lowest molecular mass is

• CH₃-CH₂-CH₂-CH₃

• CH₃-CH₂-CH(CH₃)-CH₃

• 

• CH₃-CH₂-C≡CH

Which of the following will have a meso-isomer also?

• 2-chlorobutane

• 2,3-dichlorobutane

• 2,3-dichloropentane

• 2-hydroxypropanoic acid

The smog is essentially caused by the presence of

• O₂ and O₃

• O₂ and N₂

• oxides of sulphur and nitrogen

• O₃ and N₂

In this reaction

CH₃CHO + HCN → CH₃CH(OH)CN $\stackrel{\mathrm{H}.\mathrm{OH}}{\to }$ CH₃CH(OH)COOH

an asymmetric centre is generated. The acid obtained would be

• 50% D + 50% L-isomer

• 20% D + 80% L-isomer

• D-isomer

• L-isomer

Which one of the following octahedral complexes will not show geometrical isomerism? (A and B are monodentate ligands)

• [MA₄B₂]

• [MA₅B]

• [MA₂B₄]

• [MA₃B₃]

37.

According to IUPAC nomenclature sodium nitroprusside is named as

• sodium pentacyanonitrosyl ferrate (II)

• sodium pentacyanonitrosyl ferrate (III)

• sodium nitroferricyanide

• sodium nitroferrocyanide

Which of the following is responsible for depletion of the ozone layer in the upper strata of the atmosphere ?

• Polyhalogens

• Ferrocenes

• Fullerenes

• Freons

CaC₂ + N₂ → A, product A is

• CaCN₂

• CaCN₂ and C

• CaCN₂ + N₂

• None of these

How many unit cells are present in a cube shaped ideal crystal of NaCl of mass 1.00 gm? [Atomic masses : Na = 23; Cl = 35.5]

• 2.57 × 10²¹

• 5.14 × 10²¹

• 1.28 × 10²¹

• 1.71 × 10²¹