Identify concordant titres and calculate the average volume of acid.

i) Average volume of acid

Step 1: Identify concordant titres and calculate the average volume of acid.
Concordant titres are usually within $\pm 0.10 \text{ cm}^3$ of each other. The accurate titre readings are $12.70 \text{ cm}^3$, $12.70 \text{ cm}^3$, and $12.60 \text{ cm}^3$. All three values are concordant.

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