12th class (Fsc) Chemistry unit 3 MCQs
chapter 3 MCQs 12th Class Chemistry
Group III A and Group IVA Elements:
1. which of the following has highest boiling point?
a. Phosphorus
b. Aluminium
c. Sulphur
d. Silicon
2. A gas which burns with blue flame is:
a. N2
b. CO2
c. CO
d. NO
3. Dolomite is:
a. MgCO3
b. CaCO3
c. Na2 .CO3
d. MgCO3 .CaCO3
4. Which element of III-A group is essential is very small amount for the proper growth of many plants?
a. Ti
b. Al
c. B
d. In
5. Boron is always found in nature combined with:
a. Oxygen
b. Nitrogen
c. Sulphur
d. Chlorine
6. Out of given which element has highest ionization potential value?
a. Al
b. Ga
c. B
d. In
7. Out of given which element has highest m.p?
a. In
b. B
c. TI
d. Al
8. Out of given which element has maximum density?
a. TI
b. In
c. Ga
d. Al
9. The element of which pair given pair below show only trivalency:
a. AI.TI
b. B.Ga
c. AI,B
d. AI,In
10. The element of which pair form polymeric halides?
a. B.TI
b. Al.Ga
c. AI.In
d. B.Al
11. 100g of water dissolve 3g of Na2B4 O7.10H2O at:
a. 60oC
b. 0oC
c. 100oC
d. 10oC
12. 100 g of water at 100 C dissolve Na2B4O7 ,10H2O:
a. 89.3g
b. 30.3g
c. 99.3g
d. 69.3g
13. The crystals of Na2 B4 O7 ,5H2 O are:
a. Tetragonal
b. Tetrahedral
c. Hexagonal
d. Octahedral
14. The crystals of Na2B4O7 ,10H2O are:
a. Rnombohedral
b. Triclinic
c. Trigonal
d. Monoclinic
15. The borax is a crystalline solid having color:
a. Green
b. Blue
c. Brown
d. White
16. At which temperature Na2B4O7 ,5H2O crystallizes from saturated solution?
a. Above 62oC
b. Above 40oC
c. Below 40oC
d. Below 62oC
17. The aqueous solution of borax is alkaline due to:
a. Oxidation
b. Neutralization
c. Hydrogenolysis
d. Hydrolysis
18. Borax on heating smells up into a porous mass due to;
a. Decomposition
b. Addition of water
c. Efflorescence
d. Expulsion of water
19. The reaction of borax with hydrochloric acid and water yields sodium chloride and:
a. Metabolic acid
b. Pyroboric acid
c. Orthoboric acid
d. Tetra boric acid
20. Boric acid is weak monobasic acid because it acceots one:
a. Water molecule
b. Proton
c. Electron
d. Hydroxyl ion
21. The solubility of boric acid at 100oC is:
a. 24g
b. 44g
c. 14g
d. 34g
22. The boric acid is:
a. Triprotic acid
b. Monoprotic
c. Polyprotic acid
d. Diprotic acid
23. The solution of boric acid has no effect on:
a. Blue litmus
b. Methyl orange
c. Red litmus
d. Both methyle orange and red litmus
24. The formula of teraboric acid is H2B4O7 . which may also be written as?
a. 2B2O3 .H2O
b. B2O3 .3H2O
c. B2O3 .3H2O
d. B2O3 .H2O
25. Boric acid is used in potter as a glaze because borate glazes:
a. More reactive than silicate glaze
b. More fusible that silicate glazes
c. Posses a higher coefficient of expansion
d. All of given