(a). IF both (A) and (R) are correct and (R) is the correct explanation of (A).
(b). If both (A) and (R) are correct but (R) is not the correct explanation of (A).
(c). If (A) is correct, but (R) is incorrect.
(d). If (A) is incorrect, but (R) is correct. ltbr. (e) if both (A) and (R) are incorrect.
Q. Assertion (A): Estimation of reducing substance by the use of standard `I_(2)` is called iodometry.
Reason (R): in the reaction
`I_(2)+S_(2)O_(3)^(2-)toS_(4)O_(6)^(2-)+2I^(ɵ)`
The n factor of `S_(2)O_(3)^(2-)` is one.

Answer

D

Explanation

(A) is false, because it is called iodimatry.
(R) is true `("n-factor"=(2)/(2)=1)`