Chemistry Test - 1

Atomic number of \(A =\) number of protons \(= 9\) the element '\(A\)' is flourine \((F)\) and its valency is \(-1\).

Atomic number of \(B =\) number of protons \(= 12\) the element '\(B\)' is magnesium \((Mg)\) and its valency is \(+2\).

Thus the bond formed by magnesium and flourine is an ionic bond. The formula between \(F\) and \(Mg\) is \(MgF_2\) or \(BA_2\).

The given structure is Peroxymonosulphuric acid. The image is shown below:

\(\mathrm{HO}-{\underset{\mathrm{O}}{\underset{\|}{\overset{\mathrm{O}}{\overset{\|}{\mathrm{S}}}}}}-\mathrm{O}-\mathrm{OH}\)

Peroxymonosulfuric acid, (H₂SO₅), also known as persulfuric acid, peroxysulphuric acid, or Caro's acid. In this acid, the S(VI) center adopts its characteristic tetrahedral geometry; the connectivity is indicated by the formula HO–O–S(O)₂–OH. It is one of the strongest oxidants known (E₀ = +2.51 V) and is highly explosive.

H₂SO₅ is sometimes confused with H₂S₂O₈, known as peroxydisulfuric acid. The disulfuric acid, which appears to be more widely used as its alkali metal salts, has the structure HO–S(O)₂–O–O–S(O)₂–OH.

The halogens, nitrogen and sulphur are covalently bonded to the organic compounds.

In order to detect them, the elements need to be converted into their ionic forms.

This is done by fusing the organic compound with sodium metal.

For example in Lassaigne's test for the detection of nitrogen in an organic compound, the appearance of a blue coloured compound is due to ferric ferrocyanide.

Sodium fusion extract is boiled with ferrous sulphate and then acidified with conc. sulphuric acid. Prussian blue colour complex ferric ferrocyanide confirms the presence of nitrogen.

So, Sodium (Na) metal is used to detect nitrogen in the organic compound.

\(\mathrm{S}_{\mathrm{N}} 1\) reaction occurs through the formation of carbocation as intermediate. Hence, rearrangement occurs in \(\mathrm{S}_{\mathrm{N}} 1\) reaction and not in \(\mathrm{S}_{\mathrm{N}} 2\) reaction. \(\mathrm{S}_{\mathrm{N}} 1\) reaction is favoured in presence of a polar protic solvent and a weak nucleophite. These reactions can be catalysed by the some Lewis is acid. A strong nucleophile is an aprotic solvent increases the rate of \(\mathrm{S}_{\mathrm{N}} 2\) reaction.

In sugar, the constituent particles are arranged in a specific manner. Therefore, it is a crystalline solid. 

The solids in which the constituent particles of matter are arranged and organized in a specific manner are called crystalline solids.

In coal, wax, and clay the constituent particles are arranged in a random manner. Therefore, these are an amorphous solid.

\(\mathrm{Ar, Ca}\) are isobars and \(\mathrm{D, T, P}\) are isotopes.

Isotopes: The atoms of the same element which have the same atomic number \(Z\) but differ in their mass number \(A\) are called isotopes. For example: Protium (hydrogen-1), Deuterium (hydrogen-2), Tritium (hydrogen-3).

Isobars: The atoms that have different atomic number but have the same mass number. For example: Argon, potassium, and calcium having atoms of the same mass number \(40 . \mathrm{Ar}^{40}\), \({ }_{19} \mathrm{~K}^{40},{ }_{20} \mathrm{Ca}^{40}\) where 18,19 and 20 shown as subscripts are the atomic numbers of the three elements.

\(N _{2}^{+}(13)=\sigma 1 s ^{2}, \sigma^{*} 1 s ^{2}, \sigma 2 s ^{2}, \sigma^{*} 2 s ^{2}, \pi 2 p _{ x }^{2}=\pi 2 p _{ y }^{2}, \sigma 2 p _{ z }^{1}\)

\(O _{2}(16)=\sigma 1 s ^{2}, \sigma^{*} 1 s ^{2}, \sigma 2 s ^{2}, \sigma^{*} 2 s ^{2}, \sigma 2 p _{ z }^{2}, \pi 2 p _{ x }^{2}=\pi 2 p _{ y }^{2}, \pi^{*} 2 p _{ x }^{1}=\pi^{*} 2 p _{ y }^{1}\)

\(O _{2}^{2-}(18)=\sigma 1 s ^{2}, \sigma^{*} 1 s ^{2}, \sigma 2 s ^{2}, \sigma^{*} 2 s ^{2}, \sigma 2 p _{z}^{2}, \pi 2 p _{ x }^{2}=\pi 2 p _{ y }^{2}, \pi^{*} 2 p _{ x }^{2}=\pi^{*} 2 p _{ y }^{2}\)

\(B _{2}(10)=\sigma 1 s ^{2}, \sigma^{*} 1 s ^{2}, \sigma 2 s ^{2}, \sigma^{*} 2 s ^{2}, \pi 2 p _{ x }^{1}=\pi 2 p _{ y }^{1}\)

Thus, \(O _{2}^{2-}\) does not contain unpaired electrons.

6 is the denticity of the ligand shown in the figure given below.

The ion shown in the figure is ethylenediaminetetraacetate which is a hexadentate ligand and can bind through its two N atoms or four O atoms. Hence, its denticity is 6.

1−pentanol will be the least soluble in water.

Pentan-1-ol is an alkyl alcohol that is pentane in which a hydrogen of one of the methyl groups is substituted by a hydroxy group. Alcohols are soluble in water due to hydrogen bonding. However, as the length of carbon chain increases, the extent of hydrogen bonding decreases due to bulky chain.

According to this, 1−pentanol will be the least soluble in water, among the other given alcohols.

Galena ores is best concentrated by froth-floatation method. 

Froth flotation is a process for selectively separating of hydrophobic materials from hydrophilic. This is used in mineral processing, paper recycling and waste-water treatment industries. This method is used for the concentration of sulphide ores such as galena (PbS ), zinc blende \((\mathrm{ZnS})\) and copper pyrite \(\left(\mathrm{CuF} \mathrm{eS}_{2}\right)\).