A lone pair of electrons in an atom implies

• a pair of valence electrons not involved in bonding

• a pair of electrons involved in bonding

• a pair of electrons

• a pair of valence electrons

C¹⁴ is

• a natural non-radioactive isotope

• an artificial non-radioactive isotope

• an artificial radioactive isotope

• a natural radioactive isotope

23.

A cuprous ore among the following is

• cuprite

• malachite

• chalcopyrites

• azurite

A neutral fertiliser among these compounds is

• ammonium nitrate

• urea

• CAN

• ammonium sulphate

Drying soil invariably contains

• butyric acid

• stearic acid

• lauric acid

• linoleic acid

Aluminium oxide is not reduced by chemical reactions since

• reducing agent contaminate

• the process pollute the environment

• aluminium oxide is highly stable

• aluminium oxide is reactive

A salt producing hydrocarbon among these compounds is

• ethane

• methane

• ethene

• ethyne

Octane numberis zero for

• n-octane

• iso-octane

• n-heptane

• iso-heptane

Water is a

• amphoteric acid

• aprotic solvent

• protophobic solvent

• protophilic solvent

Bio gas production is more useful when compared to the direct use of dung because

• both fuel value and fertiliser value are effectively utilised

• production of bio gas involves less labour

• fuel is quickly produced

• the fertiliser produced is a fluid