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 one of the following is present as an active ingredient in bleaching powder for bleaching action?
Ca(OCl)2
CaO2Cl
CaCl2
CaCl2
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.
|
List I (substance) |
|
List II Composition |
A. |
Plaster of Paris |
1. |
CaSO4.2H2O |
B. |
Epsomite |
2. |
CaSO4. ½ H2O |
C. |
Kieserite |
3. |
MgSO4. 7H2O |
D. |
Gypsum |
4. 5. |
MgSO4.H2O CaSO4 |
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 |
Property of the alkaline earth metals that increases with their atomic number
the solubility of their hydroxides in water
the solubility of their sulphates in water
ionisation energy
ionisation energy
Which of the following alkaline earth metal sulphates has hydration enthalpy higher than the lattice enthalpy?
CaSO4
BeSO4
BaSO4
BaSO4
B.
BeSO4
Hydration energy varies inversely with the size and in sulphates of alkaline earth metals lattice energy remains almost constant.
The order of size of alkaline earth metal is
Be2+ > Ca2+ > Sr2+ > Ba2+
Hence, BaSO4 has the hydration enthalpy higher than the lattice enthalpy.
In the case of alkali metals, the covalent character decreases in the order
MCl> MI>MBr>MF
MF> MCl> MBr>MI
MF > MCl> MI>MBr
MF > MCl> MI>MBr