List of top Chemistry Questions asked in CBSE CLASS XII

Differentiate between a double salt and a complex.

How will you confirm the presence of carbonyl group as an aldehydic group in glucose ?

A coordination compound \( \mathrm{CrCl_3 \cdot 6H_2O} \) is mixed with excess of \( \mathrm{AgNO_3} \) solution, three moles of AgCl are precipitated per mole of the compound. Write the structural formula of the coordination compound.

How will you convert chlorobenzene to p-chloroaniline ?

Write the IUPAC name of the given complex :

\( \mathrm{K_2[Zn(OH)_4]} \)

Mention the type of isomerism exhibited by the following complex :

\( \mathrm{[Pt(NH_3)(H_2O)Cl_2]} \)

Name the disease caused by the deficiency of Vitamin A.

Define conductivity.

Complete the equation :

\( \mathrm{C_6H_5{-}N_2^{+}Cl^{-}} + \mathrm{H{-}C_6H_4{-}NH_2} \rightarrow \)

Name the cell used in hearing aids and watches.

A coordination compound \( \mathrm{CrCl_3 \cdot 6H_2O} \) is mixed with excess of \( \mathrm{AgNO_3} \) solution, one mole of AgCl is precipitated per mole of the compound. Write the structural formula of the coordination compound.

How do you convert the following ?

(a) Toluene to Benzaldehyde

(b) Benzoyl chloride to Acetophenone

(c) Bromobenzene to Benzoic acid

Define polydentate ligand. Give an example.

The rate of a particular reaction quadruples when the temperature increases from 293 K to 313 K. Calculate the energy of activation (\( E_a \)) of the reaction assuming that it does not change with temperature.

(Given : log 4 = 0.60, \( R = 8.314\ \mathrm{JK^{-1}\,mol^{-1}} \))

Why is \( \mathrm{[Ti(H_2O)_6]^{3+}} \) coloured ? [Atomic number : Ti = 22]

Write the oxidation state and hybridisation of the central metal in the given complex : \( \mathrm{[Fe(CN)_6]^{3-}} \). [Atomic number : Fe = 26]

Write the IUPAC name of the given complex :

\( \mathrm{[Co(NH_3)_4(H_2O)Cl]Cl_2} \)

(a) Name two water-soluble vitamins.

(b) How will you prove the absence of free \( - \mathrm{CHO} \) group in the cyclic structure of glucose molecule ?

Name any two materials other than hydrogen that can be used as fuel in fuel cells.

Calculate emf of the following cell at 298 K :

\( \mathrm{Al(s) \,|\, Al^{3+}(aq)\,(0.1\ M) \,||\, Ni^{2+}(aq)\,(0.01\ M) \,|\, Ni(s)} \)

(Given : \( E^{\circ}_{\mathrm{Ni^{2+}/Ni}} = -0.25\ \mathrm{V} \), \( E^{\circ}_{\mathrm{Al^{3+}/Al}} = -1.66\ \mathrm{V} \), [log 10 = 1])

What are non-essential amino acids ?

Define molar conductivity.

Complete the following equation :



(i) Arrange the following compounds in increasing order of their acidic strengths :

\( \mathrm{CH_3CH(Br)CH_2COOH} \), \( \mathrm{CH_3-CH(CH_3)-COOH} \), \( \mathrm{CH_3CH_2CH(Br)COOH} \)

(ii) Why is \( \mathrm{CH_3CHO} \) more reactive than acetone towards reaction with HCN ?

(iii) Complete the equation :

\( \mathrm{CH_3{-}CH{=}O + NH_2-NH_2 \xrightarrow{H^+}} \)

Ethers are prepared by the dehydration of alcohols in presence of protic acids at 413 K. Symmetrical and unsymmetrical ethers can also be prepared by Williamson synthesis. This reaction involves \( \mathrm{S_N2} \) attack of an alkoxide ion on primary alkyl halide. If a tertiary alkyl halide is used, elimination reaction occurs and an alkene is formed, no ether is formed. C - O bond in ethers are cleaved under drastic conditions with excess of HI. When unsymmetrical ethers react with HI, the alkyl halide is formed from smaller alkyl group. If one of the alkyl group is tertiary, the alkyl halide is formed from the tertiary alkyl group because tertiary alkyl carbocation is more stable than the primary carbocation. Cleavage of alkyl aryl ethers takes place at the alkyl-oxygen bond due to more stable aryl-oxygen bond. The order of reactivity of hydrogen halides is HI > HBr > HCl. Aromatic ethers undergo electrophilic substitution reactions. The alkoxy group attached to the aromatic ring activates the ring towards electrophilic substitution and directs the incoming group to ortho- and para-positions.

Answer the following questions :

(b) Write the names of alkyl halide and sodium alkoxide used to prepare tert-butyl ethyl ether.