1
Some Basic Concepts of Chemistry
Choose the correct Answer
1.
Consider the following reaction:
xMNO4  yC2 O42   zH   xMn 2   2 yCO2 
z
H 2O
2
The value's of x, y and z in the reaction are, respectively:
2.
3.
4.
(a)
5, 2 and 16
(b)
2, 5 and 8
(c)
2, 5 and 16
(d)
5,2 and 8
A gaseous hydrcarbon gives upon combustion 0.72 g of water and 3.08 g of CO2. The empirical formula
of the hydrocarbon is:
(a)
C2 H 4
(b)
C3 H 4
(c)
C6 H5
(d)
C7 H8
Solution containing 0.34 gm AgNO3 is mixed with HCl solution containing 0.146 gm HCl. The no. of AgCl
molecules in the solution is
(a)
6.023 × 1023
(b)
6.023 × 1021
(c)
12.046 × 1020
(d)
24.092 × 1021
5 gm impure of calcium hydroxide is dissolved into 800 ml of water. In 100 ml of this solution 20 ml of
decinormal HCl is added. The acidic solution is formed neutralized by 50 ml of
N
NaOH solution.
50
Percentage purity of Ca(OH)2 is
5.
(a)
44%
(b)
5.92%
(c)
14.34%
(d)
7.5%
In the following reaction, correct statement is
 2Cr3+ + K2SO4 + 3S + 4H2O.
K2Cr2O7 + 8H+ + 3S2O3– – 
6.
7.
Molar wt
3
(a)
Equivalent weight of K2Cr2O7 =
(b)
Equivalent weight of K2Cr2O7 = Molar wt.
(c)
Equivalent weight of K2Cr2O7 =
Molar wt.
5
(d)
Equivalent weight of K2Cr2O7 =
Molar wt.
6
What weight of 80% pure NaOH required to neutralize 10% pure 100 ml 1 M H2SO4 solution?
(a)
1 gm
(b)
0.2 gm
(c)
4 gm
(d)
0.5 gm
When 20 moles of SO2 and 15 moles of O2 are passed over catalyst. 10 moles of SO3 are formed. The
volume (at NTP) of resulting gaseous mixture is
(a)
22.4 lit
(b)
448 lit
2
(c)
8.
9.
10.
11.
12.
13.
14.
112 lit
(d)
672 lit
10.6 gm mixture containing NaCl and Na2CO3 is dissolved in a solution of CaCl2 to form 5 gm CaCO3
as precipitate. The percentage of NaCl in mixture is
(a)
25%
(b)
50%
(c)
75%
(d)
20%
One gram metal (equivalent wt. 40) was burnt in excess of atmospheric oxygen. The formed metal oxide
was dissolved in 100 ml water and solution is diluted upto 5 litre. Normality of solution is
(a)
5 × 10–3
(b)
2 × 10–2 N
(c)
5N
(d)
0.2 N
x gm of NaOH required to neutralise 15 meq of HCl. To neutralise same meq of H2SO4 and H3PO4 the
weight of NaOH will be
(a)
2x g and 3x g respectively
(b)
x
x
g and g respectively
2
3
(c)
x g for each
(d)
3x g and 2x g respectively
100 ml Na2CO3.H2O solution containing 0.31 gm Na2CO3.H2O is mixed with same volume of decimolar
H2SO4 solution. Resulting solution is
(a)
Acidic
(b)
Neutral
(c)
Alkaline
(d)
Cannot determine by above data
What is the minimum molecular weight of an organic compound containing 2% carbon by weight?
(a)
200 g
(b)
400 g
(c)
600 g
(d)
800 g
4 gm propane and 48 gm O2 are allowed to react to the maximum possible extent to form only CO and
H2O. volume of CO formed is (at NTP)
(a)
5.6 lit
(b)
11.2 lit
(c)
6.1 lit
(d)
22.4 lit
For the reaction A(g)
2B(g) +
1
C(s). What is the mole fraction of A after decomposition at a
2
constant volume and temperature, if the initial pressure is 400 mmHg and the pressure at any time is 600
mmHg ?
15.
16.
(a)
0.4
(b)
0.27
(c)
0.33
(d)
0.56
A fixed weight of Ca is converted into CaCO3 and then completely neutralised by 500 mL decimolar HCl
(no acid left at the end). The calcium chloride formed is converted into plaster of paris. Weight of plaster
of paris formed is
(a)
5g
(b)
4.2 g
(c)
8.8 g
(d)
3.625 g
A metallic oxide (MO) contains 40% oxygen. The equivalent weight of M is
(a)
24
(b)
12
(c)
6
(d)
48
17.
18.
19.
20.
21.
22.
23.
3
When 400 g of a 20% solution by weight was cooled, 50 g of solute precipitated. The percentage
concentration of remaining solution is
(a)
8.57
(b)
12.25
(c)
15
(d)
7.5
10 ml of gaseous hydrocarbon on combustion gives 40 ml of CO2(g) and 50 ml of H2O (vapours). The
hydrocarbon is
(a)
C 4H 5
(b)
C8H10
(c)
C 4H 8
(d)
C4H10
4.9 g KClO3 is heated for some time then weight loss was 0.384 g. The percentage of KClO3 decomposed
is
(a)
20
(b)
30
(c)
40
(d)
80
0.5 g of a sample of H2O2 required 20 ml 1 N KMnO4 in a titration in the presence of H2SO4. Purity
of H2O2 is
(a)
17 %
(b)
34 %
(c)
51 %
(d)
68 %
The ratio of the number of molecules contained in 1g of NH3 and 1g of N2 is
(a)
17 : 28
(b)
28 : 17
(c)
17 : 14
(d)
14 : 17
150 ml
M
KMnO4 in acidic medium can oxidise completely
10
(a)
150 ml 1M Fe2+
(b)
75 ml 1M Fe2+
(c)
75 ml 1M C2O42–
(d)
150 ml 1M C2O42–
1 gm of an oxalate sample (C 2O42– + Impurities) is dissolved in water and diluted upto 100 ml.
10 ml of this solution is completely oxidised with 15 ml
N
KMnO4. The percentage purity of the sample
10
is
24.
(a)
33
(b)
66
(c)
78
(d)
90
10 ml of
N
N
N
NaOH, 30 ml of
KOH, 75 ml of Ba(OH)2 are mixed together. The normality of resulting
2
10
5
solution is
25.
(a)
0.02 N
(b)
0.2 N
(c)
0.5 N
(d)
0.05 N
A piece of Ca is disolved in 40 ml of
of
N
NaOH. The weight of Ca is
5
N
HCl completely. The excess of acid was neutralized by 15 ml
10
4
26.
27.
28.
(a)
0.24 g
(b)
0.024 g
(c)
0.012 g
(d)
0.40 g
Experimentally it was found that a metal oxide. Fraction of the metal which exists as M3+ would be
(a)
7.01%
(b)
4.08%
(c)
6.05%
(d)
5.08%
The difference in the oxidation numbers of the two types is sulphur atoms in Na2 S 4 O6 is
(a)
3
(b)
4
(c)
5
(d)
6
If the value of Avogadro number is 6.023  1023 mol 1 and the value of Boltzmann constant is
1.380  1023 JK 1 , then the number of singificant digits in the calculated value of the universal gas
constant is:
29.
30.
(a)
4
(b)
3
(c)
2
(d)
1
90 g Mohr’s salt is dissolved into 2 litre water. Equivalent weight of salt is equal to
(a)
Molar weight of salt
(b)
Molar weight / 4
(c)
Molar weight / 6
(d)
Molar weight / 8
50 ml, centimolar KMnO4 solution is just sufficient to oxidise 75ml of a H2O2 solution in the presence of
H2SO4. The correct statement for this H2O2 solution is
(a)
Molarity of H2O2 solution is 1/30
(b)
Normality of H2O2 solution is 1/30
(c)
Volume strength of H2O2 solution is 2 V
(d)
Weight percentage of H2O2 in solution is 40%