If a gas expands at constant temperature, it indicates that
kinetic energy of molecules decreases
pressure of the gas increases
kinetic energy of molecules remains the same
number of the molecules of the gas increases.
A compound formed by elements A and B crystallises in the cubic structure, where A atoms are present at the corner of a cube and B atoms are present at the face centres. The formula of the compound is
A2B2
AB3
AB
A3B
A pure crystalline substance on being heated gradually first forms a turbid liquid at constant temperature and still at higher temperature turbidity completely disappears. The behaviour is a characteristic of substance forming
allotropic crystals
liquid crystals
isomeric crystals
isomorphous crystals
With which one of the following elements silicon should be doped so as to give p- type of semiconductor?
Germanium
Arsenic
Selenium
Boron
When is the deviation is more in the behaviour of a gas from the ideal gas equation pV= nRT?
At high temperature and low pressure
At low temperature and high pressure
At high temperature and high pressure
At low temperature and low pressure
The appearance of colour in solid alkali metal halides is generally due to
F- centres
Schottky defect
Frenkel defect
Interstitial positions
When electrons are trapped into the crystalline anion vacancy, the defect is known as
Stoichiometric defect
Which one of the following is wrong statement for gases?
Gases do not have a definite shape and volume
Volume of the gas is equal to volume of container confining the gas
Confined gas exerts uniform pressure on the walls of its container in all directions.
Mass of gas can not be determined by weighing a container in which it is enclosed.
Most crystals show good cleavage because their atoms, ions or molecules are
weakly bonded together
strongly bonded together
spherically symmetrical
arranged in planes
Cyclopropane and oxygen at partial pressures 170 Torr and 570 Torr are mixed in a gas cylinder. What is the ratio of the number of moles of cyclopropane to the number of moles of oxygen?
170x42 / 570x32 = 0.39
170 / 740 = 0.23
170 / 570 = 0.30