Number of optical isomers possible for 2 - chlorobutane..........

Assertion $(A)$ : $\mathrm{NH}_3$ and $\mathrm{NF}_3$ molecule have pyramidal shape with a lone pair of electrons on nitrogen atom. The resultant dipole moment of $\mathrm{NH}_3$ is greater than that of $\mathrm{NF}_3$.

Reason $(R)$ : In $\mathrm{NH}_3$, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the $\mathrm{N}-\mathrm{H}$ bonds. $\mathrm{F}$ is the most electronegative element.

In the light of the above statements, choose the correct answer from the options given below:

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$IUPAC$ name of $C{H_2} = CH - CH{(C{H_3})_2}$ is

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Spin isomerism is shown by

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Decreasing order of stability of following carbocations is

$(A)$ $m-CH_3OPhCH_2^+$ $(B)$ $p-CH_3OPhCH_2^+$ $(C)$ $PhCH_2^+$ $(D)$ $p-NO_2PhCH_2^+$

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Light, a well-known from of energy, is treated as a from of matter, by saying that it consists of:

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The equilibrium concentration of $x, y$ and $yx_2$ are $4, 2$ and $2$ respectively for the equilibrium $2x + y \rightleftharpoons yx_2$. The value of equilibrium constant, $K_C$ is