Chemistry Test - 15

The name of the compound having the structure \(\mathrm{ClCH}_{2} \mathrm{CH}_{2} \mathrm{COOH}\) is3-chloropropanoic acid.

Aniline reacts with a mixture of sodium nitrite and hydrochloric acid and forms benzene diazonium chloride. The structure of Benzene diazonium chloride is

Benzene diazonium chloride reacts with aniline in presence of dilute hydrochloric acid and undergoes coupling reaction and produces stable azo products. In this reaction, benzene diazonium chloride acts as an electrophile in coupling with activated aniline. In this type of reaction, substitution takes place at the para position. So, the reaction of Benzene diazonium chloride with aniline in presence of dilute hydrochloric acid is as follows:

Catalytic poisoners act by getting adsorbed on the active centres on the surface of catalyst.

Catalyst poisoning refers to the effect that a catalyst can be 'poisoned' if it reacts with another compound that bonds chemically to its active surface sites.

This has two effects. The total number of catalytic sites or the fraction of the total surface area that has the capability of promoting reaction always decreases and the average distance that a reactant molecule must diffuse through the pore structure before undergoing reaction may increase.

Poisoned sites can no longer accelerate the reaction with which the catalyst was supposed to catalyze. Therefore, catalytic poisons act by getting adsorbed on the active centres on the surface of the catalyst.

Ionic species are stabilized by the dispersal of charge.

• The carboxylate ion \(\left(\mathrm{F}_{2} \mathrm{CHCOO}^{-}\right)\)is the most stable.
• The negative charge on \(\mathrm{O}\) is dispersed through resonance in the carboxylate group.
• The negative charge is further dispersed due to negative inductive effect (-I effect) of two \(\mathrm{F}\) atoms present on alpha carbon atoms.

As the temperature rises, more collisions start taking place which results in an increase in rate of the chemical reaction.

With rise in temperature, fraction of molecules possessing kinetic energy greater than the activation energy increases. Only such molecules are able to cause effective collisions and result in the formation of product. Thus, as the fraction of such molecules increases, rate of the reaction increases.

The process of passing of a precipitate into colloidal solution on adding an electrolyte is calledPeptization.

It is the process of converting is fresh precipitate into colloidal particles by shaking it with the dispersion medium in the presence of a small amount of suitable electrolyte called peptizing agent.

Generally an electrolyle is added whose one ion is common with one ion of precipitate.The particles of the precipitate absorb common ion of the electrolyte. then they get dispersed due to electrostatic repulsion.

Example: when \(\mathrm{Fe}Cl_{3}\) is added to \(\mathrm{Fe}(\mathrm{OH})_{3}\), the precipitate of hydromide changes to solution by absorbing \(Fe^{3+}\) Cons. \(\mathrm{Fe}^{3 +}\) is absorbed on \(\mathrm{Fe}(\mathrm{OH})_{3}\) and breaks into colloids.

(i) Given halide is a primary, predominantly undergo \(\mathrm{S}_{\mathrm{N}} 2\) reaction.

(i) \(\rightarrow\) (q)

(ii) Given halide is secondary, can undergo \(\mathrm{s}_{\mathrm{N}} 2\) reaction. Also, E2 reaction leads to a conjugated system. Also it may react by \(\mathrm{El}\) cb mechanism because it forms resonance stabilised carbanion.

(ii) \(\rightarrow\) (q,r,s)

(iii) It is a \(3^{\circ}\) halide and in the presence of weak base \(\mathrm{H}_{2} \mathrm{O}\), weak nucleophile \(\mathrm{H}_{2} \mathrm{O}\), it may undergo unimolecular substitution \(\left(\mathrm{S}_{\mathrm{N}} 1\right)\) and elimination (E1) reaction.

(iii) \(\rightarrow\) (p)

(iv) It may form a stable benzylic carbocation after hydride shift, hence may react by \(\mathrm{S}_{\mathrm{N}} 1\) mechanism. Also it is a secondary halide, may undergo \(\mathrm{S}_{\mathrm{N}} 2\) reaction. It may also react by E2 reaction ai it gives conjugated system. Carbanion. formed at \(\beta-C\) will be stabilised by resonance from ring, hence may undergo E1 cb mechanism.

\(\text { (iv) } \rightarrow(\mathrm{p}, \mathrm{q}, \mathrm{r} , \mathrm{s})\)

An ideal solution is a mixture in which the molecules of different species are distinguishable, however, unlike the ideal gas, the molecules in ideal solution exert forces on one another. When those forces are the same for all molecules independent of species then a solution is said to be ideal.

For an ideal solution, \(\Delta H _{\text {mixing }}=0 ; \Delta V _{\text {mixing }}=0\) and its should obey Raoult's law.

In \(\mathrm{C u S O_{4}}\), the electronic configuration of \(\mathrm{Cu}\) is \(\mathrm{[A r] 3 d^{10} 4 s^{1}}\).

\(\mathrm{C u^{2+}}:\) The electronic configuration is \(\mathrm{[A r] 3 d^{9}}\).

In \(\mathrm{Zn S O_{4}}\), the electronic configuration of \(\mathrm{Zn}\) is \(\mathrm{[A r] 3 d^{10} 4 s^{2}}\).

\(\mathrm{Z n^{2+}}:\) The electronic configuration is \(\mathrm{[A r] 3 d^{10}}\).

As we know that, a compound to be paramagnetic, it must have an unpaired electron and in \(\mathrm{C u^{2+}}\), an unpaired electron is present while \(\mathrm{Z n^{2+}}\) has no unpaired electron, so it is diamagnetic.

The rate constant has a unit for a different order of a reaction.

The rate constant, or the specific rate constant, is the proportionality constant in the equation that expresses the relationship between the rate of a chemical reaction and the concentrations of the reacting substances.

The stoichiometry of the reaction is indicated by placing stoichiometric coefficients before the chemical species. These are usually integer numbers, but in some bioenergetic processes, non-integer stoichiometries are known to pertain.

Thus, the statement i, ii, iii is correct.

More the number of upaired d-electrons, more is the magnetic moment.

Therefore, we have:

(A) \(\mathrm{C u^{2+}: 3 d^{9}}\)

No. of unpaired electrons \(=1\)

(B) \(\mathrm{Ni}^{2+}: 3 d^{8} \)

No. of unpaired electrons \(=2\)

(C) \(\mathrm{Co}^{2+}: 3 d^{7}\)

No. of unpaired electrons \(=3\)

(D) \(\mathrm{Fe}^{2+}: 3 d^{6}\)

No. of unpaired electron \(=4\)

Therefore,\({Fe}^{2+}\) has highest magnetic moment.

As evident from the image, the ratio of the number of ketonic groups in cytosine, thymine and uracil is \(1: 2: 2\)

(A) \(\mathrm{N H_{4} N O_{2}}\) is Ammonium Nitrite. The thermal decomposition occurs as follows-

\(\mathrm{NH}_{4} \mathrm{NO}_{2} \stackrel{\Delta}{\longrightarrow} \mathrm{N}_{2}+2 \mathrm{H}_{2} \mathrm{O}\)

The reaction produces Nitrogen gas and water vapour.

(B) \(\mathrm{N a N_{3}}\) is sodium azide. The thermal decomposition occurs as follows-

\(2 \mathrm{N a N_{3}} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{N a}+3 \mathrm{N_{2}}\)

The reaction produces Sodium metal and Nitrogen gas. Very pure nitrogen is obtained by this method.

(C) \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) is Ammonium dichromate. These are red coloured crystals. The thermal decomposition occurs as follows-

\(\left(\mathrm{NH}_{4}\right){ }_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} \stackrel{\Delta}{\longrightarrow} \mathrm{Cr}_{2} \mathrm{O}_{3}+\mathrm{N}_{2}+4 \mathrm{H}_{2} \mathrm{O}\)

Ammonium dichromate is thermodynamically unstable and hence it decomposes into dark green chromium (III) oxide and Nitrogen gas. The reaction occurs with flashes of light.

We can see that, \(\mathrm{N}_{2}\) is released in all the reactions.

IUPAC name of \(\left.Pt \left( NH _{3}\right)_{2} Cl \left( NO _{2}\right)\right]\) isDiamminechloridonitrito-N-platinum (II).

The oxidation state of Pt\( =+2\)

\(\left( NH _{3}\right)_{2}= \) Diammine

\(Cl= \) Chlorido

\(NO _{2} =\) Nitrito-N

So, IUPAC name is Diamminechloridonitrito-N-platinum(II).