The standard electrode potential is measured by

• electrometer

• voltmeter

• pyrometer

• galvanometer

Which one of the following defects in the crystals lowers its density?

• Frenkel defect

• Schottky defect

• F-centres

• Interstitial defect

A radioactive isotope has a half-life of 10 days. If today 125 mg is left over, what was its original weight 40 days earlier?

• 2 gm

• 600 mg 

• 1 gm

• 1.5 gm

When plants and animals decay, the organic nitrogen is converted into inorganic nitrogen. The inorganic nitrogen is in the form of

• ammonia

• elements of nitrogen

• nitrates

• nitrides

A compound A has a molecular formula C₂Cl₃OH. It reduces Fehling's solution and on oxidation, gives a monocarboxylic acid B. A can be obtained by the action of chlorine on ethyl alcohol. A is :

• chloroform

• chloral

• methyl chloride

• monochloroacetic acid

Which of the following haloalkanes is most reactive?

• 1-chloropropane

• 1-bromopropane

• 2-chloropropane

• 2-bromopropane

The reaction in which phenol differs from alcohol is:

• it undergoes esterification with carboxylic acid

• it reacts with ammonia

• it forms yellow crystals of iodoform

• it liberates H₂ with Na metal

48.

An organic compound A containing C, H and O has a pleasant odour with boiling point of 78°C. On boiling A with concentrated H₂SO₄, a colourless gas is produced which decolourises bromine water and alkaline KMnO₄. The organic liquid A is:

• C₂H₅Cl

• C₂H₅COOCH₃

• C₂H₅OH

• C₂H₆

Benzyl alcohol and sodium benzoate is obtained by the action of sodium hydroxide on benzaldehyde. This reaction is known as

• Perkin's reaction

• Cannizaro's reaction

• Sandmeyer's reaction

• Claisen condensation

A compound, containing only carbon, hydrogen and oxygen, has a molecular weight of 44. On complete oxidation it is converted into a compound of molecular weight 60. The original compound is

• an aldehyde

• an acid

• an alcohol

• an ether