Group 14 - carbon allotropes, oxides, silicon, silicates and silicones — practice questions

Question 1 · difficulty L2 · understanding

Choose the INCORRECT statement

• A. Carbon exhibits negative oxidation states along with +4 and +2 .
• B. Carbon cannot exceed its covalency more than four.
• C. Among the isotopes of carbon, ${ }^{13} \mathrm{C}$ is a radioactive isotope.
• D. $\mathrm{CO}_2$ is the most acidic oxide among the dioxides of group of 14 elements.

Question 2 · difficulty L2 · understanding

Given below are two statements : Statement I : The number of pairs among $\left[\mathrm{SiO}_2, \mathrm{CO}_2\right],\left[\mathrm{SnO}, \mathrm{SnO}_2\right],\left[\mathrm{PbO}, \mathrm{PbO}_2\right]$ and $\left[\mathrm{GeO}, \mathrm{GeO}_2\right]$, which contain oxides that are both amphoteric is 2 . Statement II : $\mathrm{BF}_3$ is an electron deficient molecule, can act as a Lewis acid, forms adduct with $\mathrm{NH}_3$ and has a trigonal planar geometry. In the light of the above statements, choose the correct answer from the options given below :

• A. Both Statement I and Statement II are false
• B. Statement I is false but Statement II is true
• C. Both Statement I and Statement II are true
• D. Statement I is true but Statement II is false

Question 3 · difficulty L2 · understanding

Which of the following material is not a semiconductor.

• A. Copper oxide
• B. Graphite
• C. Silicon
• D. Germanium

Question 4 · difficulty L2 · understanding

Given below are two statements : Statement (I) : $\mathrm{SiO}_2$ and $\mathrm{GeO}_2$ are acidic while $\mathrm{SnO}$ and $\mathrm{PbO}$ are amphoteric in nature. Statement (II) : Allotropic forms of carbon are due to property of catenation and $\mathrm{p} \pi-\mathrm{d} \pi$ bond formation. In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Statement I is false but Statement II is true
• B. Both Statement I and Statement II are false
• C. Both Statement I and Statement II are true
• D. Statement I is true but Statement II is false

Question 5 · difficulty L2 · understanding

Consider the oxides of group 14 elements $$\mathrm{SiO}_2, \mathrm{GeO}_2, \mathrm{SnO}_2, \mathrm{PbO}_2, \mathrm{CO}$$ and $$\mathrm{GeO}$$. The amphoteric oxides are

• A. $$\mathrm{SnO}_2, \mathrm{CO}$$
• B. $$\mathrm{SiO}_2, \mathrm{GeO}_2$$
• C. $$\mathrm{SnO}_2, \mathrm{PbO}_2$$
• D. $$\mathrm{GeO}, \mathrm{GeO}_2$$

Question 6 · difficulty L2 · understanding

During water-gas shift reaction

• A. water is evaporated in presence of catalyst.
• B. carbon monoxide is oxidized to carbon dioxide.
• C. carbon is oxidized to carbon monoxide.
• D. carbon dioxide is reduced to carbon monoxide.

Question 7 · difficulty L2 · understanding

The correct order of bond enthalpy ($$\mathrm{kJ~mol^{-1}}$$) is :

• A. $$\mathrm{C-C > Si-Si > Sn - Sn > Ge-Ge}$$
• B. $$\mathrm{Si-Si > C-C > Ge-Ge > Sn-Sn}$$
• C. $$\mathrm{C-C > Si-Si > Ge-Ge > Sn-Sn}$$
• D. $$\mathrm{Si-Si > C-C > Sn-Sn > Ge-Ge}$$

Question 8 · difficulty L2 · understanding

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion A : Carbon forms two important oxides - CO and CO$$_2$$. CO is neutral whereas CO$$_2$$ is acidic in nature Reason R : CO$$_2$$ can combine with water in a limited way to form carbonic acid, while CO is sparingly soluble in water In the light of the above statements, choose the most appropriate answer from the options given below :

• A. A is not correct but R is correct
• B. Both A and R are correct but R is NOT the correct explanation of A
• C. Both A and R are correct and R is the correct explanation of A
• D. A is correct but R is not correct

Question 9 · difficulty L2 · understanding

In liquation process used for tin (Sn), the metal :

• A. is reacted with acid.
• B. is dissolved in water.
• C. is brought to molten form which is made to flow on a slope.
• D. is fused with NaOH

Question 10 · difficulty L2 · understanding

Given below are two statements. Statement I : Stannane is an example of a molecular hydride. Statement II : Stannane is a planar molecule. In the light of the above statement, choose the most appropriate answer from the options given below.

• A. Both Statement I and Statement II are true.
• B. Both Statement I and Statement II are false.
• C. Statement I is true but Statement II is false.
• D. Statement I is false but Statement II is true.