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  • Solution

Which one of the following compounds will be most readily dehydrated?

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    The intermediate is carbocation which is destabilised by C = O group in the first three cases. In(d),α–hydrogen is more acidic which can be removed as water. Moreover, the positive charge on the intermediate carbocation is relatively away from the C = O group.

The O – O – H bond angle in H2O2 is

  • Solution

    O – O – H bond angle in H2O2 is 94.8°.

A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37.0ºC. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be:(R = 8.314 J/mol K) (ln 7.5 = 2.01)

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    Process is isothermal reversible expansion,
    hence ΔU = 0, therefore q = – W.Since q = +208 J, W= –208 J

The oxidation number of nitrogen in (N2H5)+ is:

  • Solution

    Let O.N. of Nitrogen be x.

    2x – 5 = + 1 ⇒x=6⁄2=3

D2O is used in

  • Solution

    D2O is used in nuclear reactors as moderator.

Some of the properties of the two species, \(NO_{3}^{-}\) and H3O+ are described below. Which one of them is correct?

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    In \(NO_{3}^{-}\), nitrogen have sp2 hybridisation, thus planar in shape. In H3O+, oxygen is in sp3 hybridisation,thus tetrahedral geometry is expected but due to presence of one lp of electrons on central oxygen atom it is pyramidal in shape.

Which of the following involves transfer of five electrons ?

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    O.N. of Mn in MnO4- is +7 and in Mn2+ it is +2.

    The difference is of 5 electrons.

Refractory metals are used in construction of furnaces because

  • Solution

    Refractory metals are used in the construction of furnaces because they can withstand high temperature e.g. silica, flint, lime, etc.Option (a) is correct

The number of ? and ?bonds in a molecule of acetonitrile are respectively

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Butene-1 may be converted to butane by reaction with

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    Alkenes combine with hydrogen under pressure and in presence of a catalyst (Ni, Pt or Pd) and form alkanes.

\(CH_{3} -CH_{2}-CH_{2}-Cl\begin{matrix}KOH\\ \rightarrow \\ alc\end{matrix}B \overset{HBr}{\rightarrow} C\begin{matrix}ether\\ \rightarrow \\ Na\end{matrix}D\)

In the above sequence of reactions, the product D is –

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Which one of the following halogen compounds is difficult to behydrolysed by SN1 mechanism?

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    Chlorobenzene does not undergo hydrolysis by SN1 mechanism because in this halogen is present on sp2 hybridised carbon atom,such halogens are relatively inert.

In reaction of KMnO4 and Mohr’s salt, FeSO4 is oxidised to

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The compound MX4 is tetrahedral. The number of ∠XMX formed in the compound are

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In the reaction ,2A + B ⟶ A2B if the concentration of A is doubled and that of Bis halved,then the rate of the reaction will:

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The gas used in air ships is :

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    Hydrogen is lighter than helium but still helium is used in ballons because hydrogne is highly explosive and reactive gas. It may lead to accident.

10 g CaCO3 gives on strong heating CO2. It gives quicklime(in grams)

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Allene (C3H4) contains :

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    Allene is H2C = C = CH2

Tetra ethyl lead is used as:

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    Knocking (metallic sound or rattle) decreases the power and increases the wear of the engine. Knocking is more if petrol contains greater percentage of straight chain hydrocarbon. It is least in case of alkene/ branched chain HC/ aromatic HC. Tetra ethyl lead dissociates into ethyl radicals which combine with some straight chain HC and thus lowering the knocking property of fuel by forming branched chain HC.

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