The importance of sodium aluminate (III) in the treatment of water is to
cause coagulation
prevent goitre and tooth decay
neutralize acidity
kill germs
What type of bond exists between an element X with atomic number 12 and Y with atomic number 17?
Dative
Covalent
Metallic
Electrovalent (ionic)
Hardness of water is mainly due to the presence of
calcium trioxocarbonate (IV) or calcium tetraoxosulphate (VI)
sodium hydroxide or magnesium hydroxide
calcium hydroxide or magnesium hydroxide
calcium chloride or sodium chloride salts
A suitable solvent for iodine and naphthalene is
water
carbon(IV) sulphide (CS2)
benzene
ethanol
Which of the following noble gases is commonly found in the atmosphere?
Neon
Xenon
Argon
Helium
