Answer :
Oxidation number or oxidation state : It represent the number of electrons lost or gained by the atoms of an element in a compound.
Oxidation numbers are generally written with the sign (+) and (-) first and then the magnitude.
Rules for Oxidation Numbers are :
- The oxidation number of a free element is always zero.
- The oxidation number of a monatomic ion equals the charge of the ion.
- The oxidation number of Hydrogen (H) is +1, but it is -1 in when combined with less electronegative elements.
- The oxidation number of oxygen (O) in compounds is usually -2.
- The oxidation number of a Group 17 element in a binary compound is -1.
- The sum of the oxidation numbers of all of the atoms in a neutral compound is zero.
- The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.
Now we have to determine the oxidation state of the elements in the compound.
(a)
Let the oxidation state of 'S' be, 'x'
Hence, the oxidation state of 'S' is, (+6)
(b)
Let the oxidation state of 'Ca' be, 'x'
Hence, the oxidation state of 'Ca' is, (+2)
(c)
Let the oxidation state of 'Br' be, 'x'
Hence, the oxidation state of 'Br' is, (+1)
(d)
Let the oxidation state of 'N' be, 'x'
Hence, the oxidation state of 'N' is, (+5)
(e)
Let the oxidation state of 'Ti' be, 'x'
Hence, the oxidation state of 'Ti' is, (+4)
(f)
Let the oxidation state of 'Na' be, 'x'
Hence, the oxidation state of 'Na' is, (+1)