In this experiment you will determine the relative formula mass, $$\(M_{\mathrm{r}}\)$$, of a basic metal carbonate, $$\(\mathrm{MCO}_{3} \cdot \mathrm{M}(\mathrm{OH})_{2}\)$$, by a titration method. FB 1 is the basic metal carbonate $$\(\mathrm{MCO}_{3} \cdot \mathbf{M}(\mathrm{OH})_{2}\)$$. FB 2 is a solution containing hydrochloric acid, HCl , and $$\(\mathbf{M C l}_{2}\)$$, prepared using $$\(\mathbf{F B} \mathbf{1}\)$$ as follows. - 22.50 g of $$\(\mathrm{FB} \mathbf{1}, \mathrm{MCO}_{3} \cdot \mathrm{M}(\mathrm{OH})_{2}\)$$, is weighed out. - $$\(\quad 100.0 \mathrm{~cm}^{3}\)$$ of $$\(5.00 \mathrm{~mol} \mathrm{dm}^{-3}\)$$ hydrochloric acid (a small excess) is added to FB 1. - The mixture is left to allow FB 1 to react completely. $$\[ \mathrm{MCO}_{3} \cdot \mathrm{M}(\mathrm{OH})_{2}(\mathrm{~s})+4 \mathrm{HCl}(\mathrm{aq}) \rightarrow 2 \mathrm{MCl}_{2}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{~g})+3 \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \]$$ - The resulting solution is made up to $$\(1.00 \mathrm{dm}^{3}\)$$ with distilled water. - This solution is FB 2. FB 3 is potassium hydroxide, KOH , of concentration $$\(5.05 \mathrm{gdm}^{-3}\)$$. FB 4 is thymolphthalein indicator. Calculations (i) Give your answers to (c)(ii), (c)(iii) and (c)(iv) to an appropriate number of significant figures. (ii) Calculate the amount, in mol, of potassium hydroxide present in $$\(25.0 \mathrm{~cm}^{3}\)$$ of FB 3 . $$\[ \text { amount of } \mathrm{KOH}= \]$$ .......................... $$\(\mathrm{mol}\)$$ (iii) Give the ionic equation for the reaction of hydrochloric acid with potassium hydroxide during the titration. Include state symbols. ....................................................................................................................................... . Hence calculate the concentration, in $$\(\mathrm{moldm}^{-3}\)$$, of hydrochloric acid in FB 2. concentration of $$\(\mathrm{HCl}=\)$$ .......................... $$\(\mathrm{moldm}^{-3}\)$$ (iv) Use the information about FB 2 and your answer to (c)(iii) to calculate the relative formula mass, $$\(M_{\mathrm{r}}\)$$, of $$\(\mathrm{MCO}_{3} \cdot \mathrm{M}(\mathrm{OH})_{2}\)$$. $$\[ M_{\mathrm{r}} \text { of } \mathrm{MCO}_{3} \cdot \mathbf{M}(\mathrm{OH})_{2}= \]$$ ..........................

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