Question

The water having more dissolved O₂ is : 

(1) boiling water 

(2) water at 80°C 

(3) polluted water 

(4) water at 4°C

Answer 1

Answer is (4) water at 4°C

On heating concentration of O₂ in water decreases. So boiling water and water at 80°C having less O₂ concentration. Polluted water also having less O₂ concentration. So water at 4°C having maximum O₂ concentration.