1.Which type of roll(s) are used in finishing process of paper making?
a) Suction roll
b) Calendering roll
c) Winding roll
d) Water mark roll
Explanation:Suction roll is used in web forming process, Calendering roll in drying process, water mark roll during pressing process, and winding roll during finishing process are used.
2. Which of the following statements are wrong?
a) Wet strength can be increased by sizing the paper with dialdehyde starch
b) Coloring can be done by water insoluble pigments
c) Grease proof paper is made from wrapping paper
d) White water cannot be reused
Explanation: The statement white water can’t be reused is wrong as white water can be reused to conserve water and additives, to prevent steam pollution, and to obtain maximum recovery of fiber.
3. Roll speed in drying section must be designed in such a way there will not be any stretching when the paper is passed through the dryer.
a) True
b) False
Explanation: The statement is false, because when paper is pulled through the dryer; the paper will shrink on drying. Hence the machine should have a tendency of stretching, so that there will be a force balance.
4. Cellulose is soluble in ________________
a) Water
b) Alkali
c) Dilute acid
d) Cuprous ammonia
Explanation:Cellulose is insoluble in water, dilute acid, alkali, and ordinary organic solvents whereas it is soluble in cuprous ammonia and in mixture of sodium hydroxide and carbon disulfide.
5. Composition of pulp required for preparing cellulose is _____________
a) Better bleach ability than paper grade pulp
b) More ash than paper grade pulp
c) More lignin than paper grade pulp
d) More pentosans than paper grade pulp
Explanation:Pulp used for cellulose preparation should have less ash, lignin, and pentosans than paper grade pulp. It must also have better bleaching ability than paper grade pulp.
6.Which of the following chemicals are soluble in water or aqueous sodium hydroxide?
a) Ethyl cellulose
b) Acetate
c) Benzyl cellulose
d) Methyl cellulose
Explanation:Ethyl cellulose and benzyl cellulose are soluble in organic solvents; Acetate is soluble in acetone, methyl acetate etc; Methyl cellulose, sodium carboxy methyl cellulose, and hydroxy ethyl cellulose are soluble in water or aqueous sodium hydroxide.
7. Dimethyl sulfoxide is soluble in water.
a) True
b) False
Explanation: Dimethyl sulfide and Dimethyl sulfoxide are insoluble in water. Dimethyl sulfoxide is miscible with most of the organic molecules excluding alkanes; hence it is used as a solvent.
8. Which of the following cellulose ether is used as thickening agent in cosmetics?
a) Ethyl cellulose
b) Benzyl cellulose
c) Methyl cellulose
d) Hydroxy ethyl cellulose
Explanation: Methyl cellulose is used as thickening agent in cosmetics whereas hydroxy ethyl cellulose is used as thickeners in food. Ethyl cellulose is used in lacquers and plastic compositions.
9. Which of the following statements regarding sodium carboxy methyl cellulose are wrong?
a) Sodium carboxy methyl cellulose has high viscosity in dilute solution
b) Sodium carboxy methyl cellulose is used as textile finish
c) Sodium carboxy methyl cellulose is non toxic
d) Sodium carboxy methyl cellulose is used as thickener in foods
Explanation: The wrong statement is that Sodium carboxy methyl cellulose is used as textile finish as hydroxy ethyl cellulose that is used as textile finish by acid precipitation even though they have almost same uses.
10. What is the molecular weight of Dimethyl sulfoxide?
a) 62
b) 77
c) 70
d) 78
Explanation: The chemical formula of Dimethyl sulfoxide is (CH3)2·S=O. Hence the molecular weight of Dimethyl sulfoxide is (1*12+3*1)*2+(1*32)+(1*16)=78.