Which of the following statements is not true for halogens?
All form monobasic oxyacids
All are oxidizing agents
Chlorine has the highest electron-gain enthalpy
All but fluorine show positive oxidation states
In the structure of ClF3, the number of lone pair of electrons on central atom ‘Cl’ is
One
Two
Three
Four
when CO2 is bubbled through a solution of barium peroxide in water then
Carbonic acid is formed
O2 is released
H2O2
No reaction occurs
Among the following compounds, which will produce POCl3 with PCl5
Only O2
O2 and CO2
CO2, O2 and P4O10
SO2, H2O, H2SO4 and P4O10
In which of the following compounds, sulphur show maximum oxidation number?
H2SO4
SO3
H2S2O7
All have same oxidation number for sulphur
Consider the reaction, H2 + X2 2HX, where X is halogen. The reactivity of halogens decrease in the order of
Cl2 > F2 > Br2 > I2
I2 > Br2 > F2 > Cl2
F2 > Cl2 > Br2 > I2
I2 > Br2 > Cl2 > F2
Sodium sulphite is used in preserving squashes and other mildly acidic foods due to
potassium salt has preservative action
potassium metabisulphite prevents oxidation
potassium metabisulphite is not influcenced by acid
sulphur dioxide and sulphurous acid formed, kill bacteria and germs
D.
sulphur dioxide and sulphurous acid formed, kill bacteria and germs
Sodium sulphite is used in preserving squashes and other mildly acidic foods because of the presence of preservatives and their high sugar content. SO2 and sulphurous acid kill the bacteria and prevent the decay of food.
K2S2O5 K2SO3 + SO2
SO2 + H2O H2SO3
The major role of fluorspar (CaF2) which is added in small quantity in the electrolytic reduction of alumina dissolved in fused cryolite (Na3AlF6) is
I. as a catalyst.
II. to make the fused mixture very conducting.
III. to lower the temperature of melting.
IV. to decrease the rate of oxidation of carbon at the anode.
I, II
II, III
I, II, III
III, IV