Chemistry Test - 32

C₄H₉ does not belongs to homologous series.

​Homologous series is a series of compounds with similar chemical properties and some functional groups differing from the successive member by CH₂.

Carbon chains of varying length have been observed in organic compounds having the same general formula.

Alkanes with general formula C_nH_2n+2, alkenes with general formula C_nH_2n and alkynes with general formula C_nH_2n-2 form the most basic homologous series in organic chemistry.

Carbon belongs to the second period and Group 14. Silicon belongs to the third period and Group 14. If atomic number of carbon is 6, the atomic number of silicon is 14.

Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it.

The compounds that contain carbon are known as organic compounds.Most abundant organic compound on earth is cellulose.

Carbohydrates are grouped into monosaccharides, disaccharides and polysaccharides. Cellulose, a storage form of carbohydrate found in plants that humans cannot digest, is among the most plentiful of the carbohydrates worldwide.Cellulose is a polymer of linear polysaccharide, with several monosaccharide glucose units. The acetal linkage is beta which distinguishes it from starch.Human beings are unable to digest cellulose because there are no sufficient enzymes for breaking down beta-acetal linkages.

The arrangement of elements in the Modem Periodic Table is based on increasing atomic number in the horizontal rows.

In 1869, Russian chemist Dmitri Mendeleev created the framework that became the modern periodic table, leaving gaps for elements that were yet to be discovered. While arranging the elements according to their atomic weight, if he found that they did not fit into the group he would rearrange them.

The maximum covalent character is shown by the compound is AlCl₃.

The proportion of covalent character in an ionic bond is decided by polarisability of the metal cation as well as the electronegativity of both elements involved in bonding. Polarisability is further decided by the density of positive charge on the metal cation. AICI₃ is considered to show maximum covalent character among the given compounds. This is because Al³⁺ bears 3 unit of positive charge and shows strong tendency to distort the electron cloud, thus the covalent character in Al-CI bond dramatically increases.

Hybridization of \(\mathrm{Fe}\) in \(\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\) is \(d^{2} s p^{3}\).

In the given complex of \(\mathrm{Fe}^{3+}\), as the co-ordination number is ' 6 ', there are two possibilities. It can be \(d^{2} s p^{3}\) or \(s p^{3} d^{2}\). But the ligand attached with central metal ion, \(\mathrm{Fe}^{3+}\), is strong field ligand so it will promote inner orbital complex, \(d^{2} s p^{3}\).

The above reaction is known as Etard reaction.

• The Etard Reaction is a chemical reaction that involves the direct oxidation of an aromatic or heterocyclic bound methyl group to an aldehyde using chromyl chloride. 
• When toluene is reacted with Chromyl Chloride, then a chromium complex is formed (Etard Complex) whose hydrolysis gives Benzaldehyde.

Alpha hydroxy ketones and Aldehydes give a positive test with Tollens' reagent.

Ketones generally don’t give positive test with Tollen’s reagent, but alpha hydroxyl ketones are an exception. Iodoform test, Ester test, etc., are used for alcohols. The litmus test, Sodium bicarbonate test and Ester test are used for carboxylic acid.

Given:

\(a=564 \mathrm{pm} = 564 \times 10^{-10}cm\)

We know that:

The density is given by the formula:

\(\rho=\frac{z M}{a^{3} N_{A}}\)

As we know that,

Each unit cell of \(\mathrm{NaCl}\) has \(4 \mathrm{Na}^{-}\)and \(4 \mathrm{Cl}^{-}\)ions.

\(\Rightarrow z=4\)

Avogadro's number, \(N_{A}=6.022 \times 10^{23} / \mathrm{mol}\)

The total mass of \(\mathrm{NaCl}\):

\(M=22.99+34.34=58.5 \mathrm{~g} / \mathrm{mol}\)

Therefore,

Density, \(\rho=\frac{z M}{a^{3} N_{A}}\)

\(=\frac{4 \times 58.5}{\left(564 \times 10^{-10}\right)^{3} \times 6.022 \times 10^{23}} \mathrm{~g~cm}^{-3}\)

\(= 2.165 \mathrm{~g~cm}^{-3}\)

(D) \(\mathrm{H}_{2} \mathrm{S}\)

Let oxidation number of sulphur in \(H_{2} S\) be \(x\).

\(\therefore 2+x=0\)

\(x=-2\)

(A) \(\mathrm{H}_{2} \mathrm{SO}_{4}\)

Let oxidation number of sulphur in \(\mathrm{H}_{2} \mathrm{SO}_{4}\) be \(x\).

\(\therefore 2+x-4(2)=0\)

\(x=+6\)

(B) \(S O_{2}\)

Let oxidation number of sulphur in \(S O_{2}\) be \(x\).

\(x+(2 \times-2)=0\)

\(x-4=0\)

\(x=+4\)

(C)\(\mathrm{H}_{2} \mathrm{SO}_{3}\)

Let oxidation number of sulphur in \(\mathrm{H}_{2} \mathrm{SO}_{3}\) be \(x\).

\(\therefore 2+x+(3)(-2)=0\)

\(x=4\)