Which of the following is incorrect for the mole fraction $(x)$?

Calculate the concentration of fluorine in $ppm$ in $500 \ g$ of toothpaste containing $0.2 \ g$ of fluorine.

State the various methods of expressing the concentration of a solution.

For the solution formed by dissolving a solid in water,choose the correct option regarding the following statements: Statement-$1$: $A$ $1$ molal aqueous glucose solution contains $180 \ g$ of glucose in $1000 \ g$ of water. Statement-$2$: $A$ solution containing $1$ mole of solute in $1000 \ g$ of water is called a $1$ molal solution.

Which of the following values changes with a change in temperature?

The mole fraction of glucose $(C_{6}H_{12}O_{6})$ in an aqueous binary solution is $0.1$. The mass percentage of water in it,to the nearest integer,is $....$.