Science (English Medium) कक्षा १२ - CBSE Important Questions

The complex [Co(NH₃)₅(NO₂)]Cl₂ is red in colour. Give IUPAC the name of its linkage isomer.

Name the method used for the refining of Nickel metal.

Which would undergo S_N1 reaction faster in the following pair and why?

 Give reasons for the following:

(CH₃)₃C–O–CH₃ on reaction with HI gives (CH₃)₃C–I and CH₃–OH as the main products and not (CH₃)₃C–OH and CH₃–I.

Out of , which is more reactive towards S_N1 reaction and why?

In the extraction of Al, impure Al₂O₃ is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?

Which would undergo S_N2 reaction faster in the following pair and why ?

Indicate the principle behind the method used for the refining of zinc.

Which form of the iron is the purest form of commercial iron?

Give reasons : n-Butyl bromide has higher boiling point than t-butyl bromide.

The presence of nitro group (−NO₂) at o/p positions increases the reactivity of haloarenes towards nucleophilic substitution reactions.

What is the principle behind the zone refining of metals?

Explain the principle of the method of electrolytic refining of metals. Give one example.

Write the structures of A, B and C in the following:

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

Give reasons:

The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.

Which reducing agent is employed to get copper from the leached low-grade copper ore?

Draw the structure of major monohalo product in each of the following reactions :

Arrange the following compounds in increasing order of their boiling points.

(a)  \[\begin{array}{cc}
\ce{CH3}\phantom{..................}\\
\backslash\phantom{...........}\\
\ce{CH - CH - CH2Br}\\
/\phantom{.............}\\
\ce{CH3}\phantom{..................}
\end{array}\]

(b) \[\ce{CH3CH2CH2CH2Br}\]

(c) \[\begin{array}{cc}
\phantom{...}\ce{CH3}\\
\phantom{}|\\
\ce{H3C - C - CH3}\\
\phantom{}|\\
\phantom{..}\ce{Br}
\end{array}\]

Arrange the following compounds in increasing order of their boiling points:

CH₃CH₂OH, CH₃−CHO, CH₃−COOH