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

Given

\[\ce{N_{2(g)} + 3H_{2(g)} -> 2NH_{3(g)}}\]; Δ_rH^θ = –92.4 kJ mol^–1

What is the standard enthalpy of formation of NH₃ gas?

Calculate the standard enthalpy of formation of CH₃OH_(l) from the following data:

\[\ce{CH3OH_{(l)} + 3/2 O2_{(g)} →CO_{2(g)} + 2H2O_{(l)}}\] ; Δ_rH^θ = –726 kJ mol^–1

\[\ce{C_{(g)} + O_{2(g)} →CO_{2(g)}}\] ; Δ_cH^θ = –393 kJ mol^–1

\[\ce{H_{2(g)} +1/2 O_{2(g)} → H2O_{(l)}}\] ; Δ_fH^θ = –286 kJ mol^–1.

Calculate the entropy change in surroundings when 1.00 mol of H₂O_(l) is formed under standard conditions. Δ_fH^θ = –286 kJ mol^–1.

A mixture of 1.57 mol of N₂, 1.92 mol of H₂ and 8.13 mol of NH₃ is introduced into a 20 L reaction vessel at 500 K. At this temperature, the equilibrium constant, K_c for the reaction 

\[\ce{N2 (g) + 3H2 (g)⇌2NH3 (g)}\] is 1.7 × 10²

Is the reaction mixture at equilibrium? If not, what is the direction of the net reaction?

Write IUPAC name of the product obtained by the ozonolysis of the following compound: 

1-Phenylbut-1-ene

Write the resonance structure of `"CO"_3^(2-)`.

Write the resonance structure of `"HCO"_3^(-)`.

What is the state of hybridisation of carbon in `"CO"_3^(2-)`.

What is the state of hybridisation of carbon in diamond?

What is the state of hybridisation of carbon in graphite?

How is an excessive content of CO₂ responsible for global warming?

Give one method for industrial preparation and one for laboratory preparation of CO₂.

Which electron displacement effect explains the following correct orders of acidity of the carboxylic acids?

\[\ce{CH3CH2COOH > (CH3)2CHCOOH > (CH3)3C.COOH}\]

Give one method for industrial preparation and one for laboratory preparation of CO.

Which electron displacement effect explains the following correct orders of acidity of the carboxylic acids?

\[\ce{Cl3CCOOH > Cl2CHCOOH > ClCH2COOH}\]

The number of atoms present in one mole of an element is equal to Avogadro number. Which of the following element contains the greatest number of atoms?

The Balmer series in the hydrogen spectrum corresponds to the transition from n₁ = 2 to n₂ = 3, 4,.......... This series lies in the visible region. Calculate the wave number of line associated with the transition in Balmer series when the electron moves to n = 4 orbit. (R_H = 109677 cm^–1)

Chlorophyll present in green leaves of plants absorbs light at 4.620 × 10¹⁴ Hz. Calculate the wavelength of radiation in nanometer. Which part of the electromagnetic spectrum does it belong to?

Assertion (A): Black body is an ideal body that emits and absorbs radiations of all frequencies.

Reason (R): The frequency of radiation emitted by a body goes from a lower frequency to higher frequency with an increase in temperature.

Threshold frequency, ν₀ is the minimum frequency which a photon must possess to eject an electron from a metal. It is different for different metals. When a photon of frequency 1.0 × 10¹⁵ s^–1 was allowed to hit a metal surface, an electron having 1.988 × 10^–19 J of kinetic energy was emitted. Calculate the threshold frequency of this metal. Show that an electron will not be emitted if a photon with a wavelength equal to 600 nm hits the metal surface.