Amongst the following,the form of water with the lowest ionic conductance at $298 \ K$ is

The $INCORRECT$ statement$(s)$ about heavy water is (are):
$(A)$ Used as a moderator in nuclear reactor.
$(B)$ Obtained as a by-product in fertilizer industry.
$(C)$ Used for the study of reaction mechanism.
$(D)$ Has a higher dielectric constant than water.
Choose the correct answer from the options given below:

Which physical constant for $H_2O$ has a higher magnitude than $D_2O$?

What is meant by 'demineralised' water and how can it be obtained?

Which of the following will cause softening of hard water?

Oxygen is slightly denser than air,so it is collected over: