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WorksheetsP BLOCK ELEMENTS CLASS 12
Total questions: 10
Worksheet time: 5mins
On addition of conc. H2SO4 to a chloride salt, colourless fumes are evolved
but in case of iodide salt, violet fumes come out. This is because
(i) H2SO4 reduces HI to I2
(ii) HI is of violet colour
(iii) HI gets oxidised to I2
(iv) HI changes to HIO3
In qualitative analysis when H2S is passed through an aqueous solution of
salt acidified with dil. HCl, a black precipitate is obtained. On boiling the
precipitate with dil. HNO3, it forms a solution of blue colour. Addition of excess
of aqueous solution of ammonia to this solution gives _________.
(i) deep blue precipitate of Cu (OH)2
(ii) deep blue solution of [Cu (NH3)4]2+
(iii) deep blue solution of Cu(NO3)2
(iv) deep blue solution of Cu(OH)2.Cu(NO3)2
On heating with concentrated NaOH solution in an inert atmosphere of CO2,
white phosphorus gives a gas. Which of the following statement is incorrect
about the gas?
(i) It is highly poisonous and has smell like rotten fish.
(ii) It’s solution in water decomposes in the presence of light.
(iii) It is more basic than NH3.
(iv) It is less basic than NH3.
On heating lead nitrate forms oxides of nitrogen and lead. The oxides formed are ______.
(i) N2O, PbO
(ii) NO2, PbO
(iii) NO, PbO
(iv) NO, PbO2
Maximum covalency of nitrogen is ______________.
3
5
4
6
Which of the following statements is wrong?
(i) Single N–N bond is stronger than the single P–P bond.
ii) PH3 can act as a ligand in the formation of coordination compound with transition elements.
(iii) NO2 is paramagnetic in nature.
(iv) Covalency of nitrogen in N2O5 is four.
A brown ring is formed in the ring test for NO3– ion. It is due to the formation of
(i) [Fe(H2O)5 (NO)]2+
(ii) FeSO4.NO2
(iii) [Fe(H2O)4(NO)2]2+
(iv) FeSO4.HNO3
Which of the following are peroxoacids of sulphur?
(i) H2SO5 and H2S2O8
(ii) H2SO5 and H2S2O7
(iii) H2S2O7 and H2S2O8
(iv) H2S2O6 and H2S2O7
In the preparation of compounds of Xe, Bartlett had taken O2+PtF6– as a base compound. This is because
(i) both O2 and Xe have same size.
(ii) both O2 and Xe have same electron gain enthalpy.
(iii) both O2 and Xe have almost same ionisation enthalpy.
(iv) both Xe and O2 are gases.
Which of the following elements can be involved in pπ–dπ bonding?
Carbon
Nitrogen
Phosphorus
Boron
