List of top Chemistry Questions

Few simple chemical tests are given below to differentiate between the pairs of compounds. Which of the following tests is not correct for differentiation?

The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain.

What is meant by the chelate effect? Give an example

p-Dichlorobenzene has higher m.p.than those of o- and m-isomers.Discuss.

Out of C6H5CH2Cl and C6H5CHClC6H5, which is more easily hydrolyzed by aqueous KOH.

What is meant by stability of a coordination compound in solution? State the factors which govern stability of complexes.

Give the oxidation state, d-orbital occupation and coordination number of the central metal ion in the following complexes: 
(i) \(K_3[Co(C_2O_4)_3] \)
(ii)\( cis-[Cr(en)_2Cl_2]Cl \)
(iii) \((NH_4)_2[CoF_4] \)
(iv) \([Mn(H_2O)_6]SO_4\)

Arrange the compounds of each set in order of reactivity towards SN2 displacement:(i)2-Bromo-2-methylbutane,1-Bromopentane,2-Bromopentane (ii)1-Bromo-3-methylbutane,2-Bromo-2-methylbutane,2-Bromo-3-methylbutane (iii)1-Bromobutane,1-Bromo-2,2-dimethylpropane,1-Bromo-2-methylbutane,1-Bromo-3-methylbutane.

\([Fe(CN)_6]^{4-}\) and \([Fe(H_2O)_6]^{2+}\) are of different colours in dilute solutions. Why?

A solution of \([Ni(H_2O)_6]^{2+}\) is green but a solution of \([Ni(CN)_4]^{2-}\) is colourless. Explain.

What is crystal field splitting energy? How does the magnitude of\( Δo\) decide the actual configuration of d-orbitals in a coordination entity?

Give the uses of freon 12, DDT, carbon tetrachloride, and iodoform.

Draw figure to show the splitting of d orbitals in an octahedral crystal field.

What is the coordination entity formed when excess of aqueous \(KCN\) is added to an aqueous solution of copper sulphate? Why is it that no precipitate of copper sulphide is obtained when \(H_2S(g)\) is passed through this solution?

Aqueous copper sulphate solution (blue in colour) gives:
(i) a green precipitate with aqueous potassium fluoride, and
(ii) a bright green solution with aqueous potassium chloride Explain these experimental results.

Explain why

(i)the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride? 

(ii)alkyl halides, though polar, are immiscible with water. 

(iii)Grignard reagents should be prepared under anhydrous conditions.

Write all the geometrical isomers of \([Pt(NH_3)(Br)(Cl)(py)\)] and how many of these will exhibit optical isomers?

Predict all the alkenes that would be formed by dehydrohalogenation of the following halides with sodium ethoxide in ethanol and identify the major alkene:

(i)1-Bromo-1 methylcyclohexane 

(ii)2-Chloro-2-methyl butane 

(iii)2,2,3-Trimethyl-3-bromopentane

Which compound in each of the following pairs will react faster in SN2 reaction with –OH? 

(i)CH3Br or CH3I 

(ii)(CH3)3CCl or CH3Cl

Draw all the isomers (geometrical and optical) of: 
(i) \([CoCl_2(en)_2]^{+}\) 
(ii)\( [Co(NH_3)Cl(en)_2] ^{2+} \)
(iii)\( [Co(NH_3)_2Cl_2(en)]^{+}\)

What are ambident nucleophiles? Explain with an example.
What are ambident nucleophiles? Explain with an example.

Give plausible explanation for each of the following: 

(i) Why are amines less acidic than alcohols of comparable molecular masses? 

(ii) Why do primary amines have higher boiling point than tertiary amines? 

(iii) Why are aliphatic amines stronger bases than aromatic amines?

Write the equations for the preparation of 1-iodobutane from(i)1-butanol (ii)1-chlorobutane (iii)but-1-ene

Write the isomers of the compound having formula C4H9Br.