241.
An amorphous solid $$(X)$$ burns in air to form a gas $$(Y)$$ which turns lime water milky. This gas decolourises aqueous solution of acidified $$KMn{O_4}.$$ Gas $$(Y)$$ reacts with oxygen to give another gas $$(Z)$$ which is responsible for acid rain. $$X, Y$$ and $$Z$$ are
| $$X$$ | $$Y$$ | $$Z$$ | |
|---|---|---|---|
| (a) | $$C$$ | $$CO$$ | $$C{O_2}$$ |
| (b) | $$S$$ | $$S{O_2}$$ | $$S{O_3}$$ |
| (c) | $$P$$ | $${P_2}{O_3}$$ | $${P_2}{O_5}$$ |
| (d) | $$S$$ | $$S{O_3}$$ | $${H_2}S{O_4}$$ |
A
(a)
B
(b)
C
(c)
D
(d)
Answer :
(b)
242.
Match the list of noble gas compounds in column I with their shapes in column II and mark the appropriate choice.
| Column I | Column II | ||
|---|---|---|---|
| a. | $$Xe{F_4}$$ | 1. | Distorted octahedral |
| b. | $$Xe{F_6}$$ | 2. | Tetrahedral |
| c. | $$Xe{O_3}$$ | 3. | Square planar |
| d. | $$Xe{O_4}$$ | 4. | Trigonal pyramidal |
A
a - 4, b - 3, c - 2, d - 1
B
a - 1, b - 2, c - 3, d - 4
C
a - 2, b - 3, c - 4, d - 1
D
a - 3, b - 1, c - 4, d - 2
Answer :
a - 3, b - 1, c - 4, d - 2
243.
Which of the following is/are not correctly matched ?
(i) $$Ge{O_2} - $$ Acidic
(ii) $$Pb{O_2} - $$ Amphoteric
(iii) $$CO - $$ Neutral
(iv) $$Si{O_2} - $$ Amphoteric
A
(i) and (iv)
B
(iv) only
C
(ii) only
D
(iii) only
Answer :
(iv) only
244. The reaction of $$KMn{O_4}$$ and $$HCl$$ results in
A
oxidation of $$Mn$$ in $$KMn{O_4}$$ and production of $$C{l_2}.$$
B
reduction of $$Mn$$ in $$KMn{O_4}$$ and production of $${H_2}.$$
C
oxidation of $$Mn$$ in $$KMn{O_4}$$ and production of $${H_2}.$$
D
reduction of $$Mn$$ in $$KMn{O_4}$$ and production of $$C{l_2}.$$
Answer :
reduction of $$Mn$$ in $$KMn{O_4}$$ and production of $$C{l_2}.$$
245. Concentrated nitric acid, upon long standing, turns yellow brown due to the formation of
A
$$NO$$
B
$$N{O_2}$$
C
$${N_2}O$$
D
$${N_2}{O_4}$$
Answer :
$$N{O_2}$$
246. Moderate electrical conductivity is shown by
A
silica
B
graphite
C
diamond
D
carborundum
Answer :
graphite
247. The number of hydrogen atom(s) attached to phosphorus atom in hypophosphorous acid is
A
three
B
one
C
two
D
zero
Answer :
two
248. Percentage of lead in lead pencil is
A
Zero
B
20
C
80
D
70
Answer :
Zero
249. In silicon dioxide
A
there are double bonds between silicon and oxygen
atoms
B
silicon atom is bonded to two oxygen atoms
C
each silicon atom is surrounded by two oxygen atoms
and each oxygen atom is bonded to two silicon atoms
D
each silicon atom is surrounded by four oxygen atoms
and each oxygen atom is bonded to two silicon atoms.
Answer :
each silicon atom is surrounded by four oxygen atoms
and each oxygen atom is bonded to two silicon atoms.
250. Regular use of the following fertilizers increases the acidity of soil?
A
Ammonium sulphate
B
Potassium nitrate
C
Urea
D
Superphosphate of lime.
Answer :
Ammonium sulphate