Question

The hot water or steam is decomposed by group 13 elements except:
A.Boron
B.Aluminium
C.Indium
D.Gallium

Answer 1

Hint: Metals react with water under either cold or hot conditions or with steam to form the oxides of those metals and also release hydrogen gas. The element which doesn’t decompose water is a metalloid.

Complete answer:
Among the different elements of group 13, boron is a metalloid and is very unreactive towards water. Most of the members of group 13 are moderately reactive at room temperature; while boron’s reactivity becomes significant only at high temperatures.
Hence, with exception to boron, all the other elements may decompose hot water or steam. The products formed after the reaction are the oxides of the elements.

So, the correct answer is option A.

Note: The most common oxidation state of group 13 is the $\left( { + 3} \right)$ state. Only for elements higher in the group, like thallium, the monovalency can be seen. These elements show an increasing trend of pH from acidic to basic, for example boron trioxide is mildly acidic in nature, aluminium and gallium oxide are amphoteric in nature, and indium oxide is nearly amphoteric in nature while thallium trioxide is a Lewis base.
As far as the physical properties of these elements are concerned, all the elements in the group 13 except boron itself are acidic in soft. Boron being a metalloid, it is thermal and an electrical insulator at room temperature, but a good conductor of heat and electricity at high temperatures.