Question 1

Which of the following Group 14 elements is not obtained form an oxide ore?&#10;A) Si&#10;B) Sn&#10;C) Pb

Accepted Answer

Pb is obtained from sulfide ore.

Question 2

Formation of diamond from graphite is favoured under:&#10;A) medium temperatures and high pressures&#10;B) high temperatures and high pressures&#10;C) high temperatures and medium pressures.

Accepted Answer

Diamond formation from graphite is favored under high temperatures and high pressures, which facilitate the transformation of the graphite structure into the more tightly bonded diamond structure.

Question 3

Why is SiH₄ more reactive than CH₄?
(i) Si is larger than C and is more susceptible to attack by nucleophiles.
(ii) Si-H bond is more polar.
(iii) Si has accessible 3d orbitals.

A) (i) and (ii)
B) All of the above
C) (ii) and (iii)

Accepted Answer

Si is larger than C and is more susceptible to attack by nucleophiles. Si-H bond is more polar. Si has accessible 3d orbitals. All these factors contribute to the higher reactivity of SiH₄ compared to CH₄.

Question 4

What is(are) the final product(s) of reaction between SiBr₄ and excess of H₂O? A) H₂SiO₄ and Br₂ B) SiO₂ and HBr C) Si(OH)₄ and HOBr

Accepted Answer

SiBr₄ reacts with water to form silicic acid (H₂SiO₄) and hydrogen bromide (HBr). However, in the presence of excess water, silicic acid undergoes further hydrolysis to form silicon dioxide (SiO₂) and water.

Question 5

Which statement is correct? A) SnCl₄ is a good reducing agent. B) PbCl₄ is stable. C) GeCl₄ is a Lewis acid.

Accepted Answer

GeCl₄ is a Lewis acid because it can accept electron pairs due to the empty d-orbitals in germanium.

Question 6

Which of the following oxides is most stable?&#10;A) GeO&#10;B) SnO&#10;C) PbO

Accepted Answer

PbO is the most stable among the given options because lead (Pb) is the heaviest element listed, and its oxides tend to be more stable due to the inert pair effect. This effect becomes more pronounced with heavier p-block elements, making their +2 oxidation state compounds, like PbO, more stable.

Question 7

The ionic carbides containing C₂^2- and C^4- ions react with water to produce: A) hydrocarbon gas B) CO₂ gas C) CO gas

Accepted Answer

Ionic carbides containing C2^2- and C4- ions react with water to produce acetylene (a hydrocarbon gas) and methane (another hydrocarbon gas), respectively.

Question 8

Determine the charge of aluminosilicate anion (Al₂Si₂O₈)^x^-. A) 2- B) 4- C) 6-

Accepted Answer

The answer of Determine the charge of aluminosilicate anion (Al₂Si₂O₈)^x^-. A)...

Question 9

Which of the following determine the properties of silicon polymers?
(i) synthesis temperature
(ii) polymer chain length
(iii) degree of cross-linking

A) (i) and (iii)
B) (ii) and (iii)
C) (i) and (iii)

Accepted Answer

The properties of silicon polymers are significantly influenced by the polymer chain length and the degree of cross-linking. Longer chains generally result in higher molecular weights and can affect the mechanical properties such as tensile strength and elasticity. The degree of cross-linking affects the polymer's rigidity, elasticity, and thermal stability.

Question 10

Some organotin and organogermanium compounds have a tendency to polymerize. How can we prevent this polymerization?&#10;A) Using bulky functional groups.&#10;B) Keeping tin and germanium in lower oxidation states.&#10;C) Running reactions at lower temperatures.

Accepted Answer

Using bulky functional groups can prevent polymerization by creating steric hindrance, which makes it difficult for the molecules to come close enough to react and form polymers.

Deck 14: The Group 14 Elements