Non-Metals – Carbon and its various forms MCQs with Explanations
Practice MCQ Questions
Ques: 1
Water gas is
Correct Answer:
(A) CO + H2
Water gas is a synthesis gas with the mixture of carbon monoxide (CO) and hydrogen (H2). Methyl alcohol is formed by water gas (CO + H2) –
CO + 2H2 → CH3OH (Catalyst process)
Ques: 2
The gas, which comes out on opening a soda water bottle, is :
Correct Answer:
(A) Carbon dioxide
Soda water or carbonated water is water that has been infused with carbon dioxide gas under pressure. The gas, which comes out on opening a soda water bottle, is carbon dioxide that produces a bubbly drink.
Ques: 3
What is the bond order of CO group?
Correct Answer:
(D)
3
In Molecular orbital theory the bond order formula can be defined as half of the difference between the number of electrons in bonding orbitals and antibonding orbitals.
Bond order = 1/2 [Nb-Na]
Where,
Nb= number of bonding electrons
Na= number of antibonding electrons
CO (Carbon monoxide) molecule has 10 valence electrons, four from carbon atom (2s22p2) and six from oxygen atom (2s22p4). According to molecular orbital diagram, molecular orbital configuration is given as
Ꟙ2s2 Ꟙ*2s2 Ꟙ2pz2π2px2 π2py2
here, Nb = 8; Na = 2
Thus, Bond order of CO = 1/2[8 – 2] = 3
Note : Here the calculations are done ignoring the 1s orbitals because there will be 2 electrons in the bonding and 2 in the antibonding.
Ques: 4
Choose the incorrect pair:
Correct Answer:
(D)
Bleaching powder – Calcium oxide
Sodium carbonate is commonly known as Washing soda. Sodium Hydrogencarbonate is commonly known as Caustic soda. Ethanoic acid is commonly known as Acetic acid. calcium oxychloride is commonly known Bleaching powder.
Ques: 5
Dry ice is –
Correct Answer:
(C) Solid CO2
Dry ice sometimes referred to as solid CO2 or dry snow is the solid (frozen) form of carbon dioxide.
Ques: 6
Which one of the following alloys is called an amalgam ?
Correct Answer:
(C) Mercury - Zinc
An amalgam is a substance formed by the reaction of Mercury with another metal.
Ques: 7
The incomplete burning of petrol and diesel produces :
Correct Answer:
(D)
carbon monoxide
In the complete combustion (burning) of hydrocarbon fuels (i.e. petrol and diesel), hydrocarbons react with oxygen and water and carbon dioxide are produced. Incomplete combustion occurs when the supply of air or oxygen is poor. In the incomplete combustion of hydrocarbon fuels water is still produced, but carbon monoxide (a poisonous gas) and carbon (as soot) are produced instead of carbon dioxide.
Ques: 8
The relative contributions of carbon dioxide (CO2), nitrous oxide (N2O), chlorofluorocarbons (CFCs) and methane (CH4) towards global warming are :
Correct Answer:
(D)
CO2 > CH4 > N2O > CFCs
The relative contribution of main greenhouse gases towards global warming are as follows :
(i) Water vapour - about 60%
(ii) Carbon dioxide (CO2) - about 26%
(iii) Methane (CH4) - about 4-9%
(iv) Ozone (O3) - about 3-7%
(v) Nitrous oxide (N2O) - about 1.5%
(vi) Chlorofluorocarbons (CFCs) and others - 0.1-0.4%
Thus, it is clear that option (d) is correct.
Ques: 9
Consider the following statements:
Assertion (A) : A dry cell cannot be charged.
Reason (R) : Dry cell has a reversible reaction.
Code :
(A) and (R) are true and (R) is the correct explanation of
(A).
Correct Answer:
(C) is true, but (R) is false.
The matters of a dry cell are there in dry form. A zinc pot is there having full of manganese dioxide, salammoniac and carbon. This cell cannot be charged because the chemical reaction in it cannot be reversed.
Ques: 10
Carbon Nanotubes (CNTs) were prepared by –
Correct Answer:
(B) Iijima
Sumio Iijima is a Japanese physicist, often cited as the inventor of carbon nanotubes.