Arrange $$\left( {NNN} \right),\left( {BrCC} \right),\left( {OOO} \right),\left( {CHH} \right),\left( {OOH} \right)$$ in increasing atomic number. The
order is ii, iii, v, i, iv.
72.
The most stable free radical among the following is
In $$ - C{H_3}, - OC{H_3}$$ and $$C{F_3},C{H_3}$$ and $$ - OC{H_3}$$ are electron donating group. Hence, they activate the benzene nucleus. In these, order of activation is $$ - OC{H_3} > - C{H_3}$$ while $$ - C{F_3}$$ group deactivates the benzene nucleus. So, it shows lower rate of electrophilic substitution on benzene ring. Thus, order of electrophilic substitution is
74.
How many $$\sigma $$ and $$\pi $$ bonds are present in $$C{H_2} = CH - CH = CH - C{H_3}?$$
No explanation is given for this question. Let's discuss the answer together.
75.
An organic compound gave $$0.4655\,g$$ of $$C{O_2}$$ on complete combustion. If the mass of the compound taken was $$0.2115\,g,$$ what is the percentage of $$C$$ in it?
76.
A sample of $$0.50\,g$$ of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in $$0.50\,mL$$ of $$0.5\,M\,{H_2}S{O_4}.$$ The residual acid required $$60\,mL$$ of $$0.5\,M$$ solution of $$NaOH$$ for neutralisation. What would be the percentage composition of nitrogen in the compound?
$$\eqalign{
& {R_f} = \frac{{{\text{Distance travelled by substance from base line }}\left( x \right){\text{ }}}}{{{\text{Distance travelled by solvent from base line }}\left( z \right)}} \cr
& {\text{For}}\,\,x:{R_f} = \frac{x}{z};\,{\text{For}}\,\,y:{R_f} = \frac{y}{z} \cr} $$
78.
Match the column I with column II and mark the appropriate choice.
No explanation is given for this question. Let's discuss the answer together.
79.
In the hydrocarbon $$\mathop {C{H_3}}\limits_6 - \mathop {CH}\limits_5 = \mathop {CH}\limits_4 - \mathop {C{H_2}}\limits_3 - \mathop C\limits_2 \equiv \mathop {CH}\limits_1 $$ the state of hybridisation of carbons 1, 3 and 5 are in the following sequence
$$\mathop {C{H_3}}\limits_{s{p^3}}^6 - \mathop {CH}\limits_{s{p^2}}^5 = \mathop {CH}\limits_{s{p^2}}^4 - \mathop {C{H_2}}\limits_{s{p^3}}^3 - \mathop C\limits_{sp}^2 \equiv \mathop {CH}\limits_{sp}^1 $$
Thus, the hybridisation of $${C^1},{C^3}$$ and $${C^5}$$ are $$sp,s{p^3},s{p^2}$$ respectively.
80.
Arrange the following compounds in order of increasing
dipole moment.
Toluene (i)
$$m$$ - dichlorobenzene (ii)
$$o$$ - dichlorobenzene (iii)
$$p$$ - dichlorobenzene (iv)
Dipole moment of $$p-$$ dichlorobenzene is zero because of symmetrical structure. $$o - $$ and $$m - $$ dichlorobenzene have higher dipole moments than toluene due to high electronegativity of chlorine than $$ - C{H_3}$$ group. Further, the $$o-$$ dichlorobenzene has higher dipole moment due
to lower bond angle than the $$m-$$ isomer. Hence, the order of increasing dipole moment is :
$$p-$$ dichlorobenzene (iv) < toluene (i) < $$m-$$ dichlorobenzene (ii) < $$o-$$ dichlorobenzene (iii)