1. Which distillation technique is used to separate butane, butylenes, and butadiene?
a) Fractional distillation
b) Vacuum distillation
c) Extractive distillation
d) Steam distillation
Explanation: Extractive distillation is used when there is small difference between their boiling points. As butane, butylenes, and butadiene have close boiling points under pressure, they are separated using extractive distillation.
2. Catalyst used in the preparation of ethanol is _________________
a) Phosphoric acid
b) Sulfuric acid
c) Hydrochloric acid
d) Nitric acid
Explanation: Synthetic ethanol is prepared by hydration of ethylene with phosphoric acid on celite catalyst.82% of ethanol produced is however manufactured using corn fermentation.
3. Catalyst used in manufacture of ethylene dichloride from ethylene and chlorine is __________
a) Hydrochloric acid
b) Ferric chloride
c) Propylene chloride
d) Poly chloroethane’s
Explanation: Catalyst used in manufacture of ethylene dichloride from ethylene and chlorine is traces of ferric chloride or ethylene dibromide. These catalysts give 90-95% yield.
4. Which enzyme is used to hydrolyse starch to maltose to manufacture ethanol by fermentation?
a) Diastase
b) Alpha-Amylase
c) Lipase
d) Beta-Amylase
Explanation: Diastase catalyses the breakdown of starch into maltose. Lipase is an enzyme that catalyses the hydrolysis of lipids. Amylase breaks down complex carbohydrates to starch.
5. Which among the following methods cannot be used for the manufacture of ethanol?
a) From fermentation of molasses
b) From lignocelluloses biomass
c) Catalytic hydrogenation of ethylene
d) From microorganisms
Explanation: Ethanol cannot be derived from microorganisms. The most widely used method for the manufacture of ethanol is from fermentation of molasses.
6.What is mash made up of in the manufacture of ethanol from molasses?
a) Ammonium nitrate + Magnesium nitrate
b) Ammonium nitrate + Magnesium nitrate + Phosphorous
c) Ammonium sulphate + Magnesium sulphate
d) Ammonium sulphate + Magnesium sulphate + Phosphorous
Explanation: Nutrients such as Ammonium sulphate, Magnesium sulphate and Phosphorous are added to molasses to support the yeast growth.
7. Denatured ethanol is safe for drinking.
a) True
b) False
Explanation: Denatured alcohol consists many additives which are harmful to the human body, such as methanol. So denatured ethanol is not safe for human consumption.
8. The pH of molasses solution in the manufacture of ethanol should be __________
a) 1-2
b) 2-3
c) 7-9
d) 4-5
Explanation:The pH of the molasses solution must be in the range of 4-5 to support yeast growth which furnishes invertase and zymase. pH is adjusted by adding sulfuric acid.
9. What is the molecular weight of vinyl chloride?
a) 63
b) 62.5
c) 64
d) 63.5
Explanation:Chemical formula of vinyl chloride is CH2=CHCl. It contains 2 carbon atoms, 3 hydrogen atoms, and 1 chlorine atom with 12, 1, and 35.5 as their atomic weights respectively. Hence the molecular weight is 12*2+3*1+35.5*1=62.5.
10. Vinyl chloride is least soluble in __________________
a) Diethyl ether
b) Water
c) Alcohols
d) Carbon tetra chloride
Explanation:Vinyl chloride with molecular weight 62.5 is slightly soluble in water but it is soluble in diethyl ether, carbon tetra chloride, and alcohols. It is available in polymer grade (99% pure).