Test: Carbon and Boron Family - Chemistry MCQ

4 moles of aluminium atom combines with 3 moles of carbon atom on heating, in order to form aluminium carbide. Aluminium carbide is ionic in nature and it also forms methane with water. Its chemical formula is given by AlC₃.

On heating, two moles of boron atom combine with one mole of a nitrogen molecule in order to form 2 moles of boron nitride. Aluminium also when reacted with nitrogen forms aluminium nitride in the same way.

Two moles of boron atoms fuse with 6 moles of sodium hydroxide in order to form 2 moles of sodium borate and three moles of hydrogen molecules. Sodium hydroxide is also known as caustic soda.

The elements of the Boron family are less electropositive than the alkaline earth metals due to their smaller size and higher ionization enthalpies. On moving down the group, the electropositive character first increases from Boron to aluminium and then decreases from gallium so thallium due to the presence of d and f orbitals which causes poor shielding.

The correct order of the increased stability of + 1 oxidation state in gallium, indium and thallium is that; gallium stability is less than that of indium and indium stability is less than that of thallium.

All the elements of Carbon family give tetrahedral and covalent halides of the type MX₄. The thermal stability follows in the decreasing order of CX₄ > Si X₄ > Ge X₄ > Sn X₄ > Pb X₄ for the elements of group 14.

The compound Stannous chloride with 5 moles of water is called bitter of tin and it is used as a mordant in dyeing as it gives bright colours. Its chemical formula is given by SnCl₂.5H₂O and it is a white crystalline solid.

Carbon dioxide is linear gas at ordinary temperature but at low temperatures, it is in solid form and also known as dry ice or drikold. it is used for storing frozen substances at a lower temperature than normal water and it is used for cooling.

The Carbon family can form two types of oxides, mono oxides of the type MO like carbon monoxide and silicon monoxide which are all basic, it can also found the oxides of the type MO₂ where carbon dioxide and silicon dioxide are acidic and the dioxide of Germanium, silicon and plumber are amphoteric.

The elements of carbon family exhibit + 2 and + 4 oxidation state. The compounds of plumbum in + 4 oxidation state are powerful oxidizing agents since +2 oxidation state of plumbum is more stable due to inert pair effect.