NCERT Class 12 Chemistry Multiple Choice Questions(MCQs) & Answers
NCERT Class 12 Chemistry
QUESTIONS
NCERT Class 12 Chemistry Optional Questions with Answers
41 Electrolytic reduction of Al2O3 to Al by Hall- Herault process is carried out
A in presence of cryolite which forms a melt with high melting point.
B in presence of cryolite which forms a melt with lower melting point.
C in presence of NaCl.
D in presence of fluorite.
Answer: in presence of cryolite which forms a melt with lower melting point.
42 The chemical composition of ‘slag’ formed during the melting process in the extraction of copper is
A Cu2O + FeS
B FeSiO3
C CuFeS2
D Cu2S + FeO
43 Natural rubber in a polymer of
A Isoprene
B Styrene
C Butadiene
D Ethyne
44 Zeigler – Natta catalyst is used in making
A LDPE
B HDPE
C PMMA
D Polystyrene
45 Bessemer converter is used in the manufacture of
A Steel
B Cast iron
C Pig iron
D Wrought iron
46 The method of zone refining of metals is based on the principle of
A greater solubility of the impurity in the molten state than in the solid.
B greater noble character of the solid metal than that of impurity.
C greater mobility of the pure metal than that of the impurity.
D higher melting point of the impurity than that of the pure metal.
Answer: greater solubility of the impurity in the molten state than in the solid.
47 Purest form of iron is
A Wrought iron
B Stainless steel
C Hard Steel
D Cast iron
48 The commercial name of polyacrylonitrile is __________ .
A Orion (acrilan)
B Bakelite
C Dacron
D PVC
49 Which of the following is not a semisynthetic polymer?
A Vulcanised rubber
B cw-polyisoprene .
C Cellulose nitrate
D Cellulose acetate
Answer: cw-polyisoprene .
50 The van’t Hoff factor (i) accounts for
A degree of solubilisation of solute.
B the extent of dissociation of solute.
C the extent of dissolution of solute.
D the degree of decomposition of solution.
Answer: the extent of dissociation of solute.