41.

A wooden box excavated from Indus valley had an activity of 1.18 × 10¹³ disintegration per minute per gm of carbon. What is the approximate age of this civilisation?

• 4000 years

• 5700 years

• 8100 years

• 6000 years

For a reaction if K_p > K_c, the forward reaction is favoured by

• low pressure

• high pressure

• high temperature

• low temperature

Railway wagon axles are made by heating iron rods embedded in charcoal powder. This process is known as

• tempering

• case hardening

• sherardising

• annealing

Thomas slag is

• CaSiO₃

• Ca₃(PO₄)₂

• MnSiO₃

• CaCO₃

Urea is preferred to ammonium sulphate as a nitrogenous fertiliser because

• it is more soluble in wate

• it is cheaper than ammonium sulphate

• it is quite stable

• it does not cause acidity in the soil

Iodoform test is not answered by

• C₂H₅OH

• CH₃OH

• CH₃COCH₃

• CH₃-CH(OH)-CH₃

Which of the following statements is incorrect regarding benzyl chloride?

• It gives white precipitate with alcoholic AgNO₃

• It is an aromatic compound with substitution in the side chain

• It undergoes nucleophilic substitution reaction

• It is less reactive than vinyl chloride

The order of reactivities of methyl halides in the formation of Grignard reagent is

• CH₃I > CH₃Br > CH₃Cl

• CH₃Cl > CH₃Br > CH₃I

• CH₃Br > CH₃Cl > CH₃I

• CH₃Br > CH₃I > CH₃Cl

The reaction of an organic compound with ammonia followed by nitration of the product gives a powerful explosive, called RDX. The organic compound is

• phenol

• toluene

• glycerine

• formaldehyde

A gas formed by the action of alcoholic KOH on ethyl iodide, decolourises alkaline KMnO₄. The gas is

• C₂H₆

• CH₄

• C₂H₂

• C₂H₄