41.

Which of the following statement is not correct?

• A furnace lined with haematite is used to convert cast iron to wrought iron

• Collectors enhance the muttability of mineral particles during froth floatation

• In vapour phase retining metal should form a volatile compound

• Copper from its low grades ores is extracted by hydrometallurgy

$$\begin{gathered} \mathrm{For} \mathrm{the} \mathrm{given}, \\ \mathrm{Sn}\to {\mathrm{Sn}}^{2+ }(0.1 \mathrm{M}) + 2\mathrm{e} \\ (\mathrm{Given} {\mathrm{E}}_{\mathrm{Sn}/{\mathrm{Sn}}^{2+}}^0= 0.136 \mathrm{V}) \\ \mathrm{The} \mathrm{electrode} \mathrm{potential} \mathrm{of} \mathrm{the} \mathrm{cell} \mathrm{at} 25° \mathrm{C} \mathrm{is}: \end{gathered}$$

• 0.165 V

• 0750 V

• 0.421 V

• 0.012 V

A storage battery contains a solution of H₂SO₄ 38% by weight. At this concentration, the van't Hoff factor is 2.50. At what temperature will the battery contents freeze? (K_f =1.80 mol' kg)

• 243.92 K

• 298 K

• 240.92 K

• 273 K

which of the following reactions of glucose can be explained only by its cyclic structure?

• Glucose forms penta acetate.

• Glucose reacts with hydroxyl amine to form an oxime.

• Penta acetate of glucose does not react with hydroxylamine.

• Glucose is oxidised by nitirc acid to gluconic acid.

Aldehydes or ketones are treated with-bromo ester in the presence of zinc to form $\mathrm{\alpha }$-hydroxy ester followed by dehydration to form $\mathrm{\alpha }$,$\mathrm{\beta }$-unsaturated ester.This reaction is known as:

• Witting reaction.

• Tischenko reaction.

• Reformatsky reaction.

• Crossed-cannazzaro's reaction.

Which among the following alcohols is most reactive with sodium wire?

• Ethanol

• 2-Propanol

• 2-Butanol

• 2-Methyl-2-butanol

The theory of enzyme mechanism that suggests a rigid, in flexible molecules is:

• coenzyme model.

• induced-fit model.

• lock and key model.

• substrate specific model.

The correct structure of the stable compound which is obtained when acetophenone react with a base C₂H₅OH is

Which of the following organic halogen compounds undergoes hydrolysis with aqueous NaOH predominantly by Sy1 mechanism?

• Ethyl iodide

• Methyl chloride

• lsopropyl chloride

• Benzyl chloride

The night blindness and pernicious anaemia are causes due to deficiency of:

• Vitamin B₆ and vitamin B_12, respectively

• Vitamin A and vitamin B₁₂ respectively

• Vitamin C and vitamin K, respectively

• Vitamin B₂ and vitamin B₁₂ respectively