Chemistry Questions and Answers Part-8

1. The gas used for artificial ripening of green fruit is
a) ethylene
b) ethane
c) carbon dioxide
d) acetylene

Answer: a
Explanation: Ethylene gas, acetylene gas liberated from calcium carbide, and ethephon are some of the commercial ripening agents used successfully in the trade and they have been widely studied for their effectiveness on initiating and accelerating the ripening process and their effect on fruit quality and health related issues. Green fruits are ripened by ethylene gas.

2. Zone refining is used for the purification of
a) Au
b) Ge
c) Ag
d) Cu

Answer: b
Explanation: Zone refining is a very useful method to get metals with very high purity such as silicon and germanium. It is also referred to as zone melting, floating zone process, and travelling melting zone.

3.The main chemical constituent of the oil of cardamom which is responsible for flavour of this oil is
a) cineole
b) engenol
c) geraniol
d) limonene

Answer: a
Explanation: The main chemical constituent of the oil of cardamom which is responsible for flavour of this oil is cineole.

4. The molecule which has the highest percentage of ionic character among the following is
a) HI
b) HF
c) HCI
d) HBr

Answer: b
Explanation: HF has the highest percentage of ionic character because F has the greatest electronegativity. F, Cl, I, and Br are all in the same group so that means their electronegativity (and thus percentage of ionic character) decreases as they go down the group in the periodic table.

5.The high reactivity of fluorine is due to
a) its high electro negativity
b) small size of fluorine atom
c) availability of d-orbitals
d) strong F - F bond

Answer: a
Explanation: The high reactivity of fluorine is due to its high electronegativity.

6. The Latin word formica means ant. The name formic acid is derived from this Latin word because
a) this acid, in ancient times, was used to eliminate ant-hills
b) this corrosive acid is secreted by ants to drive away their enemies
c) this acid was first obtained by the distillation of ants
d) ants are attracted by the odour of this acid

Answer: c
Explanation: The Latin word formica means ant. The name formic acid is derived from this Latin word because this acid was first obtained by the distillation of ants.

7. The ore which is found in abundance in India is
a) monazite
b) fluorspar
c) bauxite
d) magnetite

Answer: a
Explanation: The ore which is found in abundance in India is monazite.

8. The inherited traits of an organism are controlled by
a) RNA molecules
b) nucleotides
c) DNA molecules
d) enzymes

Answer: c
Explanation: The inherited traits of an organism are controlled by DNA molecules.
The traits an organism displays are ultimately determined by the genes it inherited from its parents, in other words by its genotype. Animals have two copies of all their chromosomes, one from each parent.

9. The heat energy produced when the human body metabolises 1 gram of fat is
a) 30 KJ
b) 1 KJ
c) 39 KJ
d) 29 KJ

Answer: c
Explanation: The heat energy produced when the human body metabolises 1 gram of fat is 39 KJ.

10. What are the number of moles of CO2 which contains 16 g of oxygen?
a) 0.5 mole
b) 0.2 mole
c) 0.4 mole
d) 0.25 mole

Answer: a
Explanation: One mole of CO2 has mass of 44 g and 32 g of O2.
So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.