Helium mixed with oxygen is used in the treatment of

Which one of the following elements will remain as liquid inside pure boiling water?

Holme's signals can be given by using

Which property of $CO_2$ makes it biologically and geo-chemically important?

Reaction of $NaCl$ with conc. $H_2SO_4$ liberates a gas,$X$ that turns moist blue litmus paper red. When gas $X$ is passed into a test tube containing egg shell powder suspended in water,another gas,$Y$ is generated which when passed through lime water makes it milky. The gases $X$ and $Y$,respectively,are

Which one of the following is correct about the stability of the given ions?