The oxidation state for manganese element in mno4¯ is:
a. +2
b. +6
c. +7
d. +8

Answer : The oxidation state of manganese (Mn) is, (+7)

Explanation :

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.

When the atoms are present in their elemental state then the oxidation number will be zero.

The oxidation number of  oxygen (O)  in compounds is usually -2.

The given compound is,

Let the oxidation state of 'Mn' be, 'x'

Therefore, the oxidation number of manganese (Mn) is, (+7)

the electrical  conductivity  of asolution  of an electrolyte is measured by determining the resistance of thesolution  between two flat or cylindrical electrodes separated by a fixed distance.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.