Short Answer TypePb(NO3)2 on heating gives a brown gas which undergoes dimerization on cooling ? Identify the gas.
Write the structures of the following:
i) BrF3
ii) XeF4
Or
What happens when:
i) SO2 gas is passed through an aqueous solution Fe3+ salt ?
ii) XeF4 reacts with SbF5 ?
Give reasons:
i) SO2 is reducing while TeO2 is an oxidizing agent.
ii) Nitrogen does not form pentahalide.
iii) ICl is more reactive than I2
i) Name the method of refining of nickel
ii) what is the role of cryolite in the extraction of aluminium
iii) what is the role of limestone in the extraction of iron from its oxides ?
The elements of 3d transition series are given as:
Sc Ti V Cr Mn Fe Co Ni Cu Zn
Answer the following:
i) Write the element which shows a maximum number of oxidation states.Give reason.
ii) Which element has the highest m.p?
iii) Which elements shows only +3 oxidation state ?
iv) which element is a strong oxidising agent in +3 oxidation state and why?
How would you account for the following?
(i) NF3 is an exothermic compound but NCl3 is not.
(ii) The acidic strength of compounds increases in the order:
PH3 < H2S < HCl
(iii) SF6 is kinetically inert.(i) As we move down the group 17, the size of the atom increases from fluorine to chlorine. The larger difference in the size of N and Cl results in the weakness of strength of N - Cl bond. On the other hand, the difference in size of N and F is small; consequently the N -F bond is quite strong. As a result, NF3 is an exothermic compound.
(ii) In a period, the electronegativity decreases in the order Cl > S > P. As a result, the loss of H+ ions decreases. Thus, the acidic strength of the hydrides decreases in the following order. HCl > H2S > PH3
(iii) The kinetic inertness of SF6 can be explained on the basis of its structure.
Long Answer Type(a) Draw the structures of the following molecules:
(i) (HPO3)3
(ii) BrF3
(b) Complete the following chemical equations:
(i) HgCl2 + PH3-->
(ii) SO3 + H2SO4 -->
(iii) XeF4 + H2O -->
OR
(a) What happens when?
(i) Chlorine gas is passed through a hot concentrated solution of NaOH?
(ii) Sulphur dioxide gas is passed through an aqueous solution of a Fe (III) salt?
(b) Answer the following:
(i) What is the basicity of H3PO3 and why?
(ii) Why does fluorine not play the role of a central atom in inter-halogen compounds?
(iii) Why do noble gases have very low boiling points?
Short Answer Type
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