Using a fully labelled diagram, describe the standard hydrogen electrode.
Use the Data Booklet to determine the standard cell potential for the reaction between $\text{Cr}^{2+}$ ions and $\text{Cr}_2\text{O}_7^{2-}$ ions in acid solution, and write a balanced equation for the reaction. $E^\circ_{\text{cell}} = \ldots\ldots\ldots\ldots\ldots\ldots\ \text{V}$.
Describe what you would see if a blue solution of $\text{Cr}^{2+}$ ions was added to an acidified solution of $\text{Cr}_2\text{O}_7^{2-}$ ions until reaction was complete.
A buffer solution is to be prepared from $1.00\ \text{mol dm}^{-3}$ ethanoic acid, $\text{CH}_3\text{CO}_2\text{H}$, and $1.00\ \text{mol dm}^{-3}$ sodium ethanoate, $\text{CH}_3\text{CO}_2\text{Na}$. Work out, to the nearest $1\ \text{cm}^3$, the amounts of each solution needed to make $100\ \text{cm}^3$ of a buffer solution with pH $5.50$. Show all steps clearly in your working. $K_a(\text{CH}_3\text{CO}_2\text{H}) = 1.79 \times 10^{-5}\ \text{mol dm}^{-3}$.
Write an equation to show the reaction of this buffer solution with added HCl.
Write an equation to show the reaction of this buffer solution with added NaOH.
Choose one reaction in organic chemistry that is catalysed by an acid, and write the structural formulae of the reactants and products in the boxes provided.