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

For an isolated system, ΔU = 0, what will be ΔS?

What are the common chemical features of alkali metals?

Why are alkali metals not found in nature?

Explain why alkali and alkaline earth metals cannot be obtained by chemical reduction methods?

Why are potassium and cesium, rather than lithium used in photoelectric cells?

When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.

Why are lithium salts commonly hydrated and those of the other alkali metal ions usually anhydrous?

Write a balanced equation for the reaction between KO₂ and water.

Write a balanced equation for the reaction between Na₂O and CO₂.

Which of the alkali metal is having least melting point?

Which one of the following alkali metals gives hydrated salts?

What is hybridization state of each carbon atom in the following compound?

C₆H₆

Indicate the σ and π bonds in the following molecules:

 CH₂ = C = CH₂

Indicate the σ and π bonds in the following molecules:

CH₃NO₂

Indicate the σ and π bonds in the following molecule:

HCONHCH₃

In the organic compound CH₂ = CH – CH₂ – CH₂ – C ≡ CH, the pair of hybridized orbitals involved in the formation of: C₂ – C₃ bond is ______.

Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.

Write the names of isotopes of hydrogen. What is the mass ratio of these isotopes?

Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

Write the formulae for the following compound:

Mercury(II) chloride