Pickles have a long shelf life and do not get spoiled for months,why?

Which of the following statements is correct for an aqueous solution of $6 \ g \ L^{-1}$ urea and $17.12 \ g \ L^{-1}$ sucrose? [Molar mass of urea $= 60 \ g \ mol^{-1}$,Molar mass of sucrose $= 342 \ g \ mol^{-1}$]

$A$ solution containing $4 \ g$ of a non-volatile organic solute per $100 \ mL$ has an osmotic pressure of $500 \ cm$ of mercury at $27^\circ C$. What is the molar mass of the solute?

Calculate the osmotic pressure of $0.03 \ mol$ of non-electrolyte solute dissolved in $0.1 \ dm^3$ of water at $300 \ K \ [R=0.0821 \ dm^3 \ atm \ mol^{-1} \ K^{-1}]$ (in $atm$)

As a result of osmosis,what happens to the volume of the solution?

$2.5 \, g$ of protein containing only glycine $(C_2H_5NO_2)$ is dissolved in water to make $500 \, mL$ of solution. The osmotic pressure of this solution at $300 \, K$ is found to be $5.03 \times 10^{-3} \, bar$. The total number of glycine units present in the protein is $....$
(Given : $R = 0.083 \, L \, bar \, K^{-1} \, mol^{-1}$)