14 th group elements (p-block) practice · Mixed difficulty

The correct answer is D (In diamond each carbon atom undergoes $S{P^3}$ hybridisation and is paramagnetic) because diamond is diamagnetic, not paramagnetic, due to the absence of unpaired electrons.

The correct answer is B (Increases the adsorbing power of the charcoal) because activation of charcoal involves increasing its surface area and porosity, thereby enhancing its ability to adsorb substances.

Option A (If both Assertion & Reason are True & the Reason is correct explanation of the Assertion) is correct because the presence of dangling bonds on the surface of diamond makes it impure.

The correct answer is A (Graphite) because graphite is a form of carbon commonly used in microphones due to its electrical conductivity and layered structure.

Option C (Flint glass) is correct because flint glass has a high refractive index and is used in optical instruments.

The correct answer is B (Zeolite) because zeolites are commonly used as water softeners.

Option D (348, 180, 167) is correct because the bond energies correlate with the catenation tendency, with C-C having the highest bond energy and Ge-Ge having the lowest among the given elements.

The correct answer is C (Zeolite) because zeolites have a three-dimensional network structure.

Option C is correct because the yellow color in the core of a non-luminous Bunsen burner flame indicates incomplete combustion of the fuel.

Option D ($\mathrm{Pb}^{2+}$) is correct because lead ions form a white precipitate with dilute HCl (PbCl2) and a yellow precipitate with KI (PbI2).

Option A (If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion) is correct because the small size of fluorine allows for effective interaction of its lone pairs with the d-orbitals of Si, stabilizing $SiF_6^{2-}$, while the larger size of chlorine prevents $SiCl_6^{2-}$ formation.

Option C is correct because silicones are hydrophobic, but the $Si-O-Si$ linkages are not moisture sensitive; they are actually quite stable.

The correct answer is D (It adsorbs coloured material) because animal charcoal has a large surface area and adsorbs impurities, including colored substances.

Option B (Carbon) is correct because carbon forms monoxide (CO) and dioxide (CO2), producer gas is made with carbon, and carbon monoxide is a reducing agent that reduces ferric oxide to iron.

Option B (Both $\mathbf{A}$ and $\mathbf{R}$ are true but $\mathbf{R}$ is not the correct explanation of $\mathbf{A}$) is correct because while both statements are true, the inert pair effect doesn't fully explain why +3 is not observed.

Option B is correct because in $(SiH_3)_3N$, the $p\pi - d\pi$ back bonding between N and Si makes it planar and less basic than $(CH_3)_3N$.

Option C (Silicones) is correct because silicones are polymers containing silicon-oxygen bonds and are used in various cosmetic and surgical procedures due to their biocompatibility and flexibility.

Option D (200 mg) is correct because one carat, the unit of weight for diamonds, is equal to 200 milligrams.

Option C is correct because silicon can expand its octet due to the availability of d-orbitals, while carbon cannot.

Option A ($\mathrm{C}{\mathrm{O}_2},\mathrm{S}{\mathrm{O}_2},{\mathrm{H}_2}\mathrm{O}$) is correct because carbon reacts with concentrated sulfuric acid to produce carbon dioxide, sulfur dioxide, and water.

Option C is correct because the assertion is true (silica is less hard than diamond), but the reason is false. In silica, each silicon atom is surrounded by four oxygen atoms, and each oxygen atom is surrounded by two silicon atoms, forming a three-dimensional network. In diamond, each carbon atom is surrounded by four carbon atoms.

Option B (Pb) is correct because lead poisoning (plumbism) can occur if lead pellets remain in the body.

Option C is correct because melting point generally decreases down the group, but Sn has a lower melting point than Pb due to its metallic structure.

The correct answer is C ($\mathrm{S}{\mathrm{i}_2}\mathrm{O}_7^{6 - }$) because this is the formula for the pyrosilicate ion.

Option D (All of these) is correct because when a mixture of sand and KNO3 is heated strongly, it produces NO2, O2, and K2SiO3.

Option A (Lead dioxide) is correct because lead dioxide (PbO2) is primarily used as an oxidizing agent and in batteries, not as a pigment in paints.

Option D (Heating lead nitrate) is correct because massicot (PbO) can be prepared by heating lead nitrate.

Option D (${[SiC{l_6}]^{2 - }}$) is correct because silicon cannot expand its coordination number beyond 4 due to the absence of available d-orbitals, making ${[SiC{l_6}]^{2 - }}$ unstable.

Option C is correct because diamond is an insulator and graphite is conducting, but the reason is false as carbon is $sp^3$ hybridized in diamond and $sp^2$ hybridized in graphite.

Option A ($S{F_4}$) is correct because it has a see-saw shape due to the presence of a lone pair, while the others are tetrahedral.