What is the difference between molality and molarity?

If $5.85 \ g$ of $NaCl$ is dissolved in $90 \ g$ of water,then find out the mole fraction of $NaCl$.

What is the approximate molality of $10 \% (w/w)$ aqueous glucose solution (in $m$)? (Molar mass of glucose $= 180 \ g \ mol^{-1}$)

Which of the following statements is true?
$(1)$ $200 \ mL$ of $0.2 \ M \ NaOH$ has the same number of moles of solute as $1000 \ mL$ of $1 \ M \ NaOH$.
$(2)$ $200 \ mL$ of $1 \ M \ NaOH$ has the same number of moles as $1000 \ mL$ of $0.2 \ M \ NaOH$.
$(3)$ $100 \ mL$ of $0.2 \ M \ NaOH$ has the same number of moles as $1000 \ mL$ of $1 \ M \ NaOH$.
$(4)$ $2000 \ mL$ of $0.2 \ M \ NaOH$ has the same number of moles as $1000 \ mL$ of $1 \ M \ NaOH$.

The reason for the change in concentration of an aqueous solution with an increase in temperature is......

If the mole fraction of the solute in liquid naphthalene $(C_{10}H_{8})$ is $0.2$,then the molality of the solution will be ............ $m$.