The first ionisation potential of Na, Mg, Al and Si are in the order

• Na <Mg>  Al <Si

• Na> Mg> Al> Si

• Na < Mg< Al> Si

• Na> Mg> Al<Si

The total number of protons in 10g of calcium carbonate is (N₀ = 6.023 x 10²³):

• 3.01 × 10²⁴

• 4.06 × 10²⁴

• 2.01 × 10²⁴

• 3.02 × 10²⁴

Which of the oxides does not react with both of an acid and alkali, is ?

• ZnO

• SnO₂

• Al₂O₃

• BeO

Bleaching action of bleaching powder is due to the liberation of

• O₂

• OCl^-

• Cl₂

• Cl^-

Which of the following is a false statement ?

• Fluorine is more electronegative than chlorine

• Nitrogen has greater IE₁ than oxygen

• Lithium is amphoteric

• Chlorine is an oxidising agent

The first ionisation potential is maximum for

• B

• N

• O

• Be

257.

A compound X on heating gives a colourless gas. This residue is dissolved in water to obtain Y. Excess CO₂ is bubbled through aqueous solution of Y when Z is formed. Z on gentle heating gives back X. The X is

• CaCO₃

• Ca(HCO₃)₂

• Na₂CO₃

• NaHCO₃

Bleaching action of SO₂ is due to its :

• oxidising property

• acidic property

• basic property

• reducing property

For the second period elements the correct increasing order of first ionisation enthalpy is:

• Li < B < Be < C < O < N < F < Ne

• Li < B < Be < C < N < O < F < Ne

• Li < Be < B < C < O < N < F < Ne

• Li < Be < B < C < N < O < F < Ne

Which of the following is an amphoteric hydroxide?

• Ca(OH)₂

• Mg(OH)₂

• Be(OH)₂

• Sr(OH)₂