Chemistry Test - 43

By the presence of a halogen atom in the ring, basic properties of aniline is increased because it is more electronegative so donation of electron will be easy, so basicity increases.

In the manufacturing of sulphuric acid, a step involves the reaction between SO₂ and O₂ in the presence of platinized asbestos to give SO₃.

SO₂ + O₂ → SO₃

​In the above reaction if the traces of arsenious oxide (As₂O₃) is used then it acts as a catalytic poison by decreasing the activity of the reaction.

The solubility \(\mathrm{S}=2.42 \times 10^{-3} \mathrm{gL}^{-1}\)

\(\mathrm{S}=\frac{2.42 \times 10^{-3} \mathrm{gL}^{-1}}{233 \mathrm{~g} \mathrm{~mol}^{-1}}=1.04 \times 10^{-5} \mathrm{molL}^{-1}\)

\(\mathrm{K}_{\mathrm{sp}}=\left[\mathrm{Ba}^{2+}\right]\left[\mathrm{SO}_{4}^{2-}\right]\)

\(\mathrm{K}_{\mathrm{sp}}=\mathrm{S} \times \mathrm{S}\)

\(\mathrm{K}_{\mathrm{sp}}=1.04 \times 10^{-5} \mathrm{molL}^{-1} \times 1.04 \times 10^{-5} \mathrm{molL}^{-1}=1.08 \times 10^{-10} \mathrm{~mol}^{2} \mathrm{~L}^{-2}\)

\(\mathrm{C}_{15} \mathrm{H}_{30}+\frac{45}{2} \mathrm{O}_2 \rightarrow 15 \mathrm{CO}_2+15 \mathrm{H}_2 \mathrm{O}\)

Given, volume of fuel \(=1 \mathrm{~L}=1000 \mathrm{ml}\)

And density of fuel \(=0.756 \mathrm{~g} / \mathrm{ml}\)

We know,

\(\mathrm{d}=\frac{\mathrm{w}}{\mathrm{v}} \)

\(\Rightarrow 0.756=\frac{\mathrm{W}}{1000} \)

\(\Rightarrow \mathrm{W}=756 \mathrm{gm} \)

\(\therefore \text { weight of fuel }=756 \mathrm{gm} \)

\(\text { Molar mass of } \mathrm{C}_{15} \mathrm{H}_{30}=15 \times 12+30=210 \)

\(\therefore \text { Moles of } \mathrm{C}_{15} \mathrm{H}_{30}=\frac{756}{210}\)

\(\therefore\) weight of fuel \(=756 \mathrm{gm}\)

Molar mass of \(\mathrm{C}_{15} \mathrm{H}_{30}=15 \times 12+30=210\)

\(\therefore\) Moles of \(\mathrm{C}_{15} \mathrm{H}_{30}=\frac{756}{210}\)

From equation you can see,

1 mole of \(\mathrm{C}_{15} \mathrm{H}_{30}\) react with \(\frac{45}{2}\) mole of \(\mathrm{O}_2\)

\(\therefore \frac{756}{210}\) moles of \(\mathrm{C}_{15} \mathrm{H}_{30}\) react with \(\frac{45}{2} \times \frac{756}{210}\) moles of \(\mathrm{O}_2\)

\(\therefore\) Moles of \(\mathrm{O}_2\) required \(=\frac{45}{2} \times \frac{756}{210}\)

\(\therefore\) Mass of \(\mathrm{O}_2\) required \(=\frac{45}{2} \times \frac{756}{210} \times 32=2592 \mathrm{~g}\)

Also,

From 1 mole of \(\mathrm{C}_{15} \mathrm{H}_{30} 15\) moles of \(\mathrm{CO}_2\) formed

\(\therefore\) From \(\frac{756}{210}\) moles of \(\mathrm{C}_{15} \mathrm{H}_{30} 15 \times \frac{756}{210}\) moles of \(\mathrm{CO}_2\) formed

\(\therefore\) Moles of \(\mathrm{CO}_2\) formed \(=15 \times \frac{756}{210}\)

\(\therefore\) Mass of \(\mathrm{CO}_2\) formed \(=15 \times \frac{756}{210} \times 44= 2376 \mathrm{~g}\)

In Benzylamine, a lone pair of electrons is again present on nitrogen (N). But here, nitrogen is attached to a \(s p^{3}\) hybridised carbon and not to the benzene ring. Hence, lone pairs of electrons on nitrogen are not involved in any resonance with the benzene ring. Therefore, lone pairs of electrons are localised here on nitrogen atoms and will be readily available for donation. Thus, benzylamine is a stronger base. Hence, benzylamine is a stronger base than aniline because the lone pair of electrons on the nitrogen atom in aniline is delocalised.

Molar mass of \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}= 12 \times 2+1 \times 4+16 \times 2=60 \mathrm{~g} \mathrm{~mol}^{-1}\)

Moles of \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}=\frac{2.5 \mathrm{~g}}{60 \mathrm{~g} \mathrm{~mol}^{-1}}=0.0417 \mathrm{~mol}\)

Mass of benzene in \(\mathrm{kg}=\frac{75 \mathrm{~g}} { 1000 \mathrm{~g} \mathrm{~kg}^{-1}}=75 \times 10^{-3} \mathrm{~kg}\)

Molality of \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}=\frac{\text { Moles of } \mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}}{\mathrm{~kg} \text { of benzene }}\) \(=\frac{0.0417 \mathrm{~mol} \times 1000 \mathrm{~g} \mathrm{~kg}^{-1}}{75 \mathrm{~g}}\)\(=0.556 \mathrm{~mol} \mathrm{~kg}^{-1}\)

The reaction that is between zinc and concentrated sulfuric acid, it does not evolve hydrogen gas because Concentrated sulphuric acid and zinc react to form Zinc sulfate, water, and sulfur dioxide. The concentrated sulphuric acid acts as an oxidizing agent.

\(2 \mathrm{H}_{2} \mathrm{SO}_{4}+\mathrm{Zn} \rightarrow \mathrm{ZnSO}_{4}+2 \mathrm{H}_{2} \mathrm{O}+\mathrm{SO}_{2}\)

There is no evolution of hydrogen gas in the above reaction.

Given,

Power of the bulb \(=100 \mathrm{watt}=100 \mathrm{~J} \mathrm{~s}^{-1}\)

Wavelength, \(\lambda=400 \times 10^{-9} m\)

Planck's constant,\(h=6.626 \times 10^{-34} \mathrm{Js}\)

The speed of light,\(=3 \times 10^{8} \mathrm{~m} \mathrm{~s}^{-1}\)

Energy of one photon,\(E=h \nu\)

\(=\frac{h c} {\lambda}\)

\(=\frac{6.626 \times 10^{-34} \times 3 \times 10^{8} }{400 \times 10^{-9} \mathrm{}}\)

\(=4.969 \times 10^{-19} \mathrm{~J}\)

Number of photons emitted \(=\frac{\text{Power of the bulb}}{\text{Energy of one photon}}\)

\(=\frac{100 }{4.969 \times 10^{-19} }\)

\(=2.012 \times 10^{20} \mathrm{~s}^{-1}\)

Coke : It is used as reducing agent in carbon reduction methods. (in metallurgical process)

Diamond : It is a allotrope of carbon in which each carbon is sp3 hybridised.

Fullerene : It contains pentagonal & hexagonal rings (cage like structure)

Graphite : It is soft solid because graphite layers are bonded with weak Vander Wall attractions.