161.

Diagonal relationship is for :

• Li - Na

• Be - Mg

• Si - Cl

• B - Si

Among NH₃, HNO₃, NaN₃ and Mg₃N₂ the number of molecules having nitrogen in negative oxidation state is

• 1

• 2

• 3

• 4

Oxygen and sulphur both are the member of same group in periodic table but H₂O is liquid while H₂S is gas because

• molecular weight of water is more

• electronegativity of sulphur is more

• H₂S  is weak acid

• water molecules are having weak hydrogen bonds between them

Diffusion of helium gas is four times faster than

• CO₂

• SO₂

• NO₂

• O₂

The pair of elements having approximately equal ionisation potential is

• Al, Ga

• Al, Si

• Al, Mg

• Al, B

Isoelectronic pair among the following is

• Ca and K

• Ar and Ca²⁺

• K and Ca²⁺

• Ar and K

On adding 1 g arsenic to 80 g benzene, the freezing' point of benzene is lowered by 0.19°C. The formula of arsenic is

• As

• As₂

• As₃

• As₄

When a metal atom combines with a non-metal atom, the non-metal atom will

• lose electrons and decrease in size

• lose electrons and increase in size

• gain electrons and decrease in size

• gain electrons and increase in size 

Born-Haber cycle can be used to estimate

• electronegativity

• electron affinity

• ionic radii

• All of these

Which is heaviest ?

• 25g mercury

• 2 mol carbon dioxide

• 2 mol water

• 4 g-atom of oxygen