Assertion (A): Excessive use of chlorinated synthetic pesticides causes soil and water pollution. 
Reason (R): Such pesticides are non-biodegradable. 
(i) Both A and R are correct, and R is the correct explanation of A. 
(ii) Both A and R are correct, but R is not the correct explanation of A. 
(iii) Both A and R are not correct. 
(iv) A is not correct but R is correct. 

–I effect ∝ Acidic strength

+I effect ∝ Basic strength

*  Most stable anion due to maximum –I effect.

*  Most acidic

with increase in separation of screen from slits plane, fringe width increases.

Excessive nitrate in drinking water causes methemoglobinemia

Excessive nitrate in drinking water causes methemoglobinemia

Release of toxic/undesirable materials in the environment.