371.

Magnesium powder burns in air to give:

• Mg (NO₃)₂ and Mg₃N₂

• MgO and Mg₃N₂

• MgO only

• MgO and Mg(NO₃)₂

A hydrated solid X on heating initially gives a monohydrated compound X,Y upon heating above 373 K leads to an anhydrous white powder Z , X and Z respectively are :

• Baking soda and dead burnt plaster.

• Baking soda and soda ash

• Washing soda and dead burnt plaster

• Washing soda and soda ash

The correct statements among (a) to (d) are:

a) Saline hydrides produce H₂ gas when reacted with H₂O

b) Reaction of LiAlH₄ with BF₃ leads to B₂H₆

c) PH₃ and CH₄ are electrons- rich and electron- precise hydrides, respectively.

d) HF and CH₄ are called as molecular hydrides.

• a, b, c and d

• a, b and c only

• a, c and d only

• c and d only

Which one of the alkali metals, forms only the normal oxide, M₂O on heating in air?

• Rb

• K

• Li

• Li

In the replacement reaction



The reaction will be most favourable if M happens to be

• Na

• K

• Rb

• Rb

Which of the following compounds has the lowest melting point? 

• CaBr₂

• CaI₂

• CaF₂

• CaF₂

Which one of the following is present as an active ingredient in bleaching powder for bleaching action?

• Ca(OCl)₂

• CaO₂Cl

• CaCl₂

• CaCl₂

On heating which of the following releases CO₂ most easily?

• K₂CO₃

• Na₂CO₃

• MgCO₃

• MgCO₃

What is the value of electron gain enthalpy of Na⁺ if IE₁ of Na = 5.1 eV?

• -5.1 eV

• -10.2 eV

• +2.55 eV

• +2.55 eV

Match (I) with list (II) for the  compositions of substances and select the correct answer using the code given below the lists.

• A	B	C	D
  3	4	1	2

• A	B	C	D
  2	3	4	1

• A	B	C	D
  1	2	3	5

• A	B	C	D
  1	2	3	5