Question:
Why is BiH3 the strongest reducing agent amongst all the hydrides of Group 15 elements?
Answer:
This is because as we move down the group, the size increases, as a result, length of E-H bond increases and its strength decreases, so that the bond can be broken easily to release H2 gas. Hence, BiH3 is the strongest reducing agent.
The p-Block Elements.
Q 1.
How is O3 estimated quantitatively?
Q 2.
Name three oxoacids of nitrogen. Write the disproportionation reaction of that oxoacid of nitrogen in which nitrogen is in +3 oxidation state.
Q 3.
Explain why inspite of nearly the same electronegativity, nitrogen forms hydrogen bonding while chlorine does not.
Q 4.
Why is BiH3 the strongest reducing agent amongst all the hydrides of group 15 elements? (C.B.S.E. 2013)
Q 5.
Discuss the trends in chemical reactivity of group 15 elements.
Q 6.
Explain why does the stability of oxoacids of chlorine increase in the order given below:
HClO < HClO2 < HClO3 < HClO4
Q 7.
Match the compounds given in Column I with the hybridization and shape given in Column II and mark the correct option.
Q 8.
Match the items of Column I and Column II and mark the correct option.
Q 9.
Complete the following reactions:
(i)C2H2 + O2 -> (ii) 4Al + 3 O2 ->
Q 10.
Mention three areas in which H2SO4 plays an important role.
Q 11.
Write the conditions to maximise the yield of H2SO4 by Contact process.
Q 12.
Justify the placement of O, S, Se, Te and Po in the same group’of the periodic table in terms of electronic configuration, oxidation state and hydride formation.
Q 13.
Explain why fluorine forms only one oxoacid, HOF.
Q 14.
Write a balanced equation for the hydrolytic reaction of PC is in heavy water.
Q 15.
What happens when H3PO4 is heated?
Q 16.
Reduction potentials of some ions are given below. Arrange them in decreasing order of oxidizing power.
Q 17.
In the preparation of H2S06 by contact process, why is S03 not absorbed directly in water to form H2S04?
Q 18.
Write a balanced chemical equation, for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.
Q 19.
Write the structure of pyrophosphoric acid.
Q 20.
Out of H2O and H2S, which one has higher bond angle and why?
Q 21.
Assertion (A): HNO3 makes from passive.
Reason (R): HNO3 forms a protective layer of ferric nitrate on the surface of iron.
Q 22.
What happens when sulp’hur dioxide is passed through an aqueous solution of Fe(III) salt?
Q 23.
Why has it been difficult to study the chemistry of radon?
Q 24.
Explain why NH3 is basic while BiH3 is only feebly basic.
Q 25.
Why does nitrogen show catenation properties less than phosphorus ? (C.B.S.E. Foreign 2009)
Q 26.
Why is dioxygen a gas but sulphur a solid?
Q 27.
How is nitrogen prepared in the laboratory? Write the chemical equations of the reactions . involved.
Q 28.
Give the resonating structures of N02 and N2O5.
Q 29.
Write main differences between the properties of white phosphorus and red phosphorus.
Q 30.
Why does nitrogen show catenation properties less than phosphorus?
Q 31.
A brown ring is formed in the ring test for NO3 ion. It is due to the formation of
Q 32.
PH3 forms bubbles when passed slowly in water but NH3 dissolves. Explain.
Q 33.
An amorphous solid "A"bums in air to form a gas "B"which turns lime water milky. The gas is also produced as a by-product during roasting of sulphide ore. This gas decolourises acidified aqueous KMnO4 solution and reduces Fe3+ to Fe+2. Identify the solid "A"and the gas "B"and write the reactions involved.
Q 34.
What is the covalence of nitrogen in N2O5 ?
Q 35.
What happens when PCl5 is heated?
Q 36.
What is the basicity of H3PO4?
Q 37.
List the important sources of sulphur.
Q 38.
Write the order of thermal stability of the – hydrides of Group 16 elements.
Q 39.
Give two examples to show the anomalous behaviour of fluorine.
Q 40.
Discuss the trends in chemical reactivity of group 15 elements.
Q 41.
How is nitrogen prepared in the laboratory? Write the chemical equations of the reactions . involved.
Q 42.
Give the resonating structures of N02 and N2O5.
Q 43.
Why does R3P=0 exist but R3N=0 does not (R is an alkyl group) ?
Q 44.
. Nitrogen exists as diatomic molecule and phosphorus as P4. Why?
Q 45.
Which aerosols deplete ozone?
Q 46.
How are XeO3 and XeOF4prepared?
Q 47.
Why do noble gases have comparatively large atomic size?
Q 48.
List the uses of neoirand argon gases.
Q 49.
Why are pentahalides more covalent than trihalidcs ?
Q 50.
Why is N2 less reactive at room temperature?
