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Quiz
CHEMISTRY
Stoichiometry
Straight Objective Type
1. Nitrogen containing organic compound when fused with sodium metal forms:
(A) NaNO2
(B) NaCN
(C) NaNH2
(D) NaNC
2. The violet colour obtained during the test of sulphur by Lassaigne’s test is due to the formation of ;
(A) Na2[Fe(CN)5S]
(B) Na2[Fe(CN)5NO]
(C) Na2[Fe(CN)6]
(D) Na4[Fe(CN)5NOS
3. 0.5 g of an organic compound containing nitrogen on Kjeldahlising required 29 mL 0.2 N H2SO4 for complete
neutralization of ammonia. The percentage of nitrogen in the compound is:
(A) 34.3
(B) 16.2
(C) 21.6
(D) 14.8
4. 0.20 g of a hydrocarbon on combustion gave 0.66 g CO2. The percentage of hydrogen in the hydrocarbon is about:
(A) 33
(B) 45
(C) 10
(D) 90
5. Empirical formula of an organic compound is CH 2. Mass of one mole of it is 42 g. The molecular formula of the
compound is:
(A) CH2
(B) C2H4
(C) C3H6
(D) C4H8
6. 0.759 g of a silver salt of a dibasic organic acid on ignition left 0.436 g metallic silver. The equivalent mass of the
acid is:
(A) 70
(B) 108
(C) 60
(D) 50
7. 20 mL of CH4 is mixed with 60 mL of oxygen and the mixture is exploded in an eudiometer tube. If all
measurements are made at the same temperature and pressure, the volume of unreacted oxygen is:
(A) 10 mL
(B) 20 mL
(C) 30 mL
(D) 40 mL
8. An organic compound containing carbon, hydrogen and oxygen contains 52.2% carbon and 13.04% hydrogen.
Vapour density of compound is 23. Its molecular formula will be:
(A) C2H6O
(B) C3H8O
(C) C4H8O
(D) C5H10O
9. In the estimation of nitrogen by Duma’s method 1.18 g of an organic compound gave 224 mL of N 2 at NTP. The
percentage of nitrogen in the compound is:
(A) 20.0
(B) 11.8
(C) 47.5
(D) 23.7
10. Sodium fusion extract, obtained from aniline, on treatment with iron (II) Sulphate and H 2SO4 in presence of air
gives a Prussian blue precipitate. The blue colour is due to the formation of:
(A) Fe4[Fe(CN)6]3
(B) Fe3[Fe(CN)6]2
(C) Fe4[Fe(CN)6]2
(D) Fe[Fe(CN)6]3
11. When FeSO4 is added in the sodium extract the compound formed is:
(A) only Na4[Fe(CN)6]
(B) only Fe(OH)2
(C) only Na2SO4
(D) mixture of these three
12. 0.73 g of organic compound on oxidation gave 1.32 g of carbon dioxide. The percentage of carbon in the given
compound will be:
(A) 49.32
(B) 59.32
(C) 29.32
(D) 98.64
13. Fractional distillation is used to separate liquids which differ in their b.p. by:
(A) 5oC
(B) 10o to 20oC
(C) 30 – 80oC
14. Which of the following are correct for purification by stream distillation?
(A) impurities must be non-volatile
(B) the liquid must be completely immiscible with water
(C) the vapour pressure of the liquid must be sufficiently high
(D) all of these
(D) 3oC
Quiz
15. Which of the following are used as absorbent in column chromatography?
(A) silica gel
(B) Alumina
(D) charcoal
CHEMISTRY
(D) all of these
16. Analysis of an organic compound gave 74% C, 8.65% H and 17.3 % N. What is the empirical formula of the
compound?
(A) C5H8N
(B) C10H12N
(D) C5H7N
(D) C10H14N
17. A hydrocarbon has empirical formula (CH2) and its density is 1.25 g L-1 at STP. The molecular formula of the
compound is:
(A) C2H4
(B) C3H6
(C) C3H8
(D) C6H8
18. 0.6 g of a silver salt of a carboxylic acid on ignition gave 0.36 g of pure silver. If molar mass of the compound is 219
mol-1, then the basicity of the acid is:
(A) 4
(B) 3
(C) 2
(D) 1
19. Let a compound contains C, H, S, N and Cl. In the detection of chlorine, sodium fusion extract is heated with few
drops of concentrated HNO3 and then silver nitrate solution is added to obtain white precipitate of AgCl. Addition of
HNO3 before AgNO3 is required
(A) to prevent hydrolysis of NaCN and Na2S
(B) to form S4N4; which prevent the formation of AgCl
(C) to prevent the formation of NO and NO2
(D) to convert –CN and S2- ions into volatile HCN and H2s, otherwise, they will interfere (by forming AgCN and Ag2s)
20. The sulphur content of cystine is 26.7%. Given that cystine contains two sulphur atoms, molecular weight of cystine is
approximately
(A) 120
(B) 240
(C) 100
(D) 60
21. An organic compound has carbon and hydrogen percentages in the ratio of 6 : 1; carbon and oxygen percentages in
the ratio of 3 : 4. The compound has the empirical formula
(A) CH2O
(B) CH4O
(C) C2H6O
(D) CHO2
22. Tyrosine is one of the amino acids present in protein. Its content in protein is 0.22% and its molecular weight is 181 g
mol-1. Lowest molecular mass of protein is
(A) 18100
(B) 2200
(C) 82273
(D) 18132
23. 0.16 g of a dibasic organic acid required 25 cm 2 of 0.1 M NaOH for complete neutralization. The molecular mass of
the acid is
(A) 45
(B) 90
(C) 64
(D) 128
24. 9.9 g amide with molecular formula C4H5NxOy on heating with alkali librated 1.7 g of ammonia. If the percentage of
oxygen is 33.33% then the ratio of ‘N’ and ‘O’ atoms in the compound is
(A) 1 : 1
(B) 1 : 2
(C) 2 : 3
(D) 3 : 2
25. Lassaigne’s test is not shown by diazonium salts because they
(A) from NH3 gas on heating much before the reaction with sodium
(B) from N2 gas on heating much before the reaction with sodium
(C) they are highly volatile and evaporate before the reaction with sodium
(D) all of these
Numerical Problems
This section contains 10 numerical type questions.
26. 0.2 g of an organic compound produced 0.677 g of CO2 and 0.1384 g of water on combustion with CuO. Calculate
the percentage by mass of carbon and hydrogen in the organic compound.
27. IN an estimated by Duma’s method 0.15 g of an organic substance produced 22.5 mL of N 2 collected over KOH
solution at 22oC and 720 mm pressure. Calculate the percentage of nitrogen by mass in the organic compound.
Quiz
CHEMISTRY
28. 0.6 g of an organic compound was Kjeldahlised and the evolved ammonia was absorbed in 90 mL N/9 H 2SO4. The
excess of acid for complete neutralization required 20 mL 0.1 N NaOH. Calculate the percentage of nitrogen in the
compound.
29. 0.147 g of an organic compound containing chlorine was heated with nitric acid and silver nitrate and gave 0.287 g
of silver chloride. Calculate the percentage of chlorine in the compound.
30. 1.5 g of an organic compound in a quantitive determination of phosphorus gave 2.5090 g of Mg 2P2O7. Calculate the
percentage of phosphorus in the compound.
31. When analysed by the combustion method, 0.20 g of an organic substance yielded (I) 0.147 g of carbon dioxide and
0.12 g of water and (II) 74.6 mL of nitrogen gas at NTP. Find the empirical formula of the substance.
Answers
1. (B)
2. (D)
3. (B)
4. (C)
5. (C)
6. (A)
7. (B)
8. (A)
9. (D)
10. (A)
11. (D)
12. (A)
13. (B)
14. (D)
15. (D)
16. (C)
17. (A)
18. (B)
19. (D)
20. (B)
21. (A)
22. (C)
23. (D)
24. (B)
25. (B)
26. C = 92.3%, H = 7.7%
29. Cl = 48.27%
27. N = 15.98%
30. P = 46.7%
28. N = 18.68%
31. CH4N2O