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

Which of the two structures (A) and (B) given below is more stabilised by resonance? Explain.

\[\ce{\underset{(A)}{CH3COOH}}\] and \[\ce{\underset{(B)}{CH3CO\overset{Θ}{O}}}\] 

Assertion (A): Energy of resonance hybrid is equal to the average of energies of all canonical forms.

Reason (R): Resonance hybrid cannot be presented by a single structure.

Calculate the atomic mass (average) of chlorine using the following data :-

Why do elements in the same group have similar physical and chemical properties?

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Lithium and oxygen

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Magnesium and nitrogen

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Aluminium and iodine

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Silicon and oxygen

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Element 71 and fluorine

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Phosphorus and fluorine

Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?

What is the wavelength of light emitted when the electron in a hydrogen atom undergoes a transition from an energy level with n = 4 to an energy level with n = 2?

Calculate the wave number for the longest wavelength transition in the Balmer series of atomic hydrogen.

What transition in the hydrogen spectrum would have the same wavelength as the Balmer transition n = 4 to n = 2 of He⁺ spectrum?

Emission transitions in the Paschen series end at orbit n = 3 and start from orbit n and can be represented as v = 3.29 × 10¹⁵ (Hz) [1/3² – 1/n²]

Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.

Calculate the wavelength for the emission transition if it starts from the orbit having radius 1.3225 nm and ends at 211.6 pm. Name the series to which this transition belongs and the region of the spectrum.

Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?

\[\ce{PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)}\]

Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?

\[\ce{CaO (s) + CO2 (g) ⇌ CaCO3 (s)}\]

Two students performed the same experiment separately and each one of them recorded two readings of mass which are given below. Correct reading of mass is 3.0 g. On the basis of given data, mark the correct option out of the following statements.

Calculate the average atomic mass of hydrogen using the following data: