Question

Which one of the following is non-metal?
A. Borax
B. Washing Soda
C. Common salt
D. Phosphorus

Answer 1

Hint: In the options given first of all try to see which is element, atom, or compound. Then after seeing the element, check whether it is metal or non-metal.

Complete step by step answer:
Borax is the sodium salt of tetra boric acid,$H_2{B}_4{O}_7$.Borax is found naturally in dried lakes of Tibet, Ceylon and India. It can be made from colemanite. Borax occurs in three forms.
Ordinary or prismatic borax-Its molecular formula is $N{a}_2{B}_4{O}_7.1O{H}_{2}O$.It contains 10 water of crystallization molecules. It can be obtained when crystallisation will take place below 60℃ .
Octahedral or jeweller’s borax -It contains five molecules of crystallization. It can be obtained when crystallisation will take place above 60℃.
Borax glass is in anhydrous form-It is formed when heated till no water of crystallization molecule is present.
Washing Soda-Its molecular formula is $N{a}_{2}C{O}_3$ and the chemical name is Sodium Carbonate. It has many different names like soda ash and soda crystals. It has a wide range of applications like it is used in the glass industry, softening agent and it is also used in food cooking. It is basic in nature. It is manufactured through the Leblanc process. In this Leblanc process the raw materials are common salt, sulphuric acid, limestone and coal.
While on the other hand, Common salt is the common name form sodium chloride with chemical formula $NaCl$. It is formed by the reaction between sodium cation and chloride anion.
So, in all the given options Phosphorous is the only nonmetal having atomic number twelve and atomic mass thirty.

Therefore, from the above explanation the correct option is (D).

Note:
Non-metals are generally poor conductors of electricity. They are non-ductile.