Science (English Medium) Class 11 - CBSE Question Bank Solutions for Chemistry

How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?

What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?

The first ionization enthalpy values (in kJmol^–1) of group 13 elements are:-

How would you explain this deviation from the general trend?

Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.

Which one of the following statements is incorrect in relation to ionization enthalpy?

Calculate the wavelength, frequency and wave number of a light wave whose period is 2.0 × 10^-10s.

Arrange the following type of radiations in increasing order of frequency:

1. radiation from microwave oven
2. amber light from traffic signal
3. radiation from FM radio
4. cosmic rays from outer space and
5. X-rays.

Nitrogen laser produces radiation at a wavelength of 337.1 nm. If the number of photons emitted is 5.6 × 10²⁴, calculate the power of this laser.

Neon gas is generally used in the signboards. If it emits strongly at 616 nm, calculate

1. the frequency of emission,
2. distance traveled by this radiation in 30 s
3. energy of quantum and
4. number of quanta present if it produces 2 J of energy.

Although both CO₂ and H₂O are triatomic molecules, the shape of H₂O molecule is bent while that of CO₂ is linear. Explain this on the basis of dipole moment.

Write the significance/applications of dipole moment.

Define electronegativity.

How does electronegativity differ from electron gain enthalpy?

Explain with the help of suitable example polar covalent bond.

Arrange the bonds in order of increasing ionic character in the molecules: LiF, K₂O, N₂, SO₂ and ClF₃.

Which out of NH₃ and NF₃ has higher dipole moment and why?

At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?

The pressure of 1 g of an ideal gas A at 27 °C is found to be 2 bar. When 2 g of another ideal gas B is introduced in the same flask at the same temperature the pressure becomes 3 bar. Find a relationship between their molecular masses.

The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at 20 °C and one bar will be released when 0.15g of aluminum reacts?

The density of a gas is found to be 5.46 g/dm³ at 27 °C at 2 bar pressure. What will be its density at STP?