iran-konkur 2021 Q227

iran-konkur · Other · konkur-riazi_1400_specialized Not Maths
227 – If at room temperature, $0.7$ g of potassium hydroxide is added to $125$ mL of cold water, regarding the resulting solution, how many of the following statements are correct? ($\mathrm{g\cdot mol^{-1}}$: $\mathrm{H=1, O=16, K=39}$; neglect the change in volume of the solution due to adding the solid substance.)
  • $250$ mL of it completely neutralizes $2.5\times10^{-2}$ mol of HCl.
  • The molar concentration of $\mathrm{OH^{-}(aq)}$ in it is $10^{12}$ times the molar concentration of $\mathrm{H^{+}(aq)}$.
  • In $50$ mL of this solution, in total, $0.01$ mol of cations and anions exist.
  • If $1.4$ g of another potassium hydroxide is added to this solution, $[\mathrm{OH^{-}}]$ will be 3 times greater.

(1) 1 (2) 2 (3) 3 (4) 4
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\textbf{227 –} If at room temperature, $0.7$ g of potassium hydroxide is added to $125$ mL of cold water, regarding the resulting solution, how many of the following statements are correct? ($\mathrm{g\cdot mol^{-1}}$: $\mathrm{H=1, O=16, K=39}$; neglect the change in volume of the solution due to adding the solid substance.)

\begin{itemize}
    \item $250$ mL of it completely neutralizes $2.5\times10^{-2}$ mol of HCl.
    \item The molar concentration of $\mathrm{OH^{-}(aq)}$ in it is $10^{12}$ times the molar concentration of $\mathrm{H^{+}(aq)}$.
    \item In $50$ mL of this solution, in total, $0.01$ mol of cations and anions exist.
    \item If $1.4$ g of another potassium hydroxide is added to this solution, $[\mathrm{OH^{-}}]$ will be 3 times greater.
\end{itemize}

\hfill (1) 1 \qquad (2) 2 \qquad (3) 3 \qquad (4) 4

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