1. Schottky defect in a crystal is observed when

A. an ion leaves its normal site and occupies an interstitial site
B. unequal number of cations and anions are missing from the lattice
C. density of the crystal is increased
D. equal number of cations and anions are missing from the lattice
Answer :   equal number of cations and anions are missing from the lattice
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2. In a closed flask of $$5\,L,$$ $$1.0\,g$$  of $${H_2}$$  is heated from $$300$$  to $$600 K.$$  Which statement is not correct?

A. Pressure of the gas increases
B. The rate of collision increases
C. The number of moles of gas increases
D. The energy of gaseous molecules increases
Answer :   The number of moles of gas increases
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3. If the ratio of masses of $$S{O_3}$$  and $${O_2}$$  gases confined in a vessel is 1 : 1, then the ratio of their partial pressures would be

A. 5 : 2
B. 2 : 5
C. 2 : 1
D. 1 : 2
Answer :   2 : 5
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4. Two vessels containing gases $$A$$ and $$B$$  are interconected as shown in the figure. The stopper is opened, the gases are allowed to mix homogeneously. The partial pressures of $$A$$ and $$B$$  in the mixture will be, respectively
States of Matter Solid, Liquid and Gas mcq question image

A. 8 and 5 atm
B. 9.6 and 4 atm
C. 4.8 and 2 atm
D. 6.4 and 4 atm
Answer :   4.8 and 2 atm
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5. $$\alpha ,v$$  and $$u$$ represent most probable velocity, average velocity and root mean square velocity respectively of a gas at a particular temperature. The correct order among the following is

A. $$u > v > \alpha $$
B. $$v > u > \alpha $$
C. $$\alpha > u > v$$
D. $$u > \alpha > v$$
Answer :   $$u > v > \alpha $$
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6. Pressure remaining the same, the volume of a given mass of an ideal gas increases for every degree centigrade rise in temperature by definite fraction of its volume at

A. $${0^ \circ }C$$
B. absolute zero
C. its critical temperature
D. its Boyle's temperature
Answer :   $${0^ \circ }C$$
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7. A closed container contains equal number of moles of two gases $$X$$  and $$Y$$  at a total pressure of $$710\,mm$$  of $$Hg.$$  If gas $$X$$  is removed from the mixture, the pressure will

A. become double
B. become half
C. remain same
D. become one-fourth.
Answer :   become half
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8. A liquid can exist only

A. between triple point and critical temperature
B. at any temperature above the melting point
C. between melting point and critical temperature
D. between boiling and melting temperature
Answer :   between boiling and melting temperature
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9. The fraction of total volume occupied by the atoms present in a simple cube is

A. $$\frac{\pi }{6}$$
B. $$\frac{\pi }{{3\sqrt 2 }}$$
C. $$\frac{\pi }{{4\sqrt 2 }}$$
D. $$\frac{\pi }{4}$$
Answer :   $$\frac{\pi }{6}$$
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10. The root mean square speeds at $$STP$$  for the gases $${H_2},{N_2},{O_2}$$   and $$HBr$$  are in the order

A. $${H_2} < {N_2} < {O_2} < HBr$$
B. $$HBr < {O_2} < {N_2} < {H_2}$$
C. $${H_2} < {N_2} = {O_2} < HBr$$
D. $$HBr < {O_2} < {H_2} < {N_2}$$
Answer :   $$HBr < {O_2} < {N_2} < {H_2}$$
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