Is citric acid stronger than tartaric acid?

No, you can prove it by looking at the pka for each

citric acid pKa about 6.4
tartaric acid pKa about 3.6

Thus, tartaric acid is stronger.

To determine whether citric acid is stronger than tartaric acid, we need to consider their relative acidic strengths. There are a couple of ways to determine this, including comparing their pKa values, acidity constants, or conducting experiments.

Firstly, pKa values are useful in comparing acid strengths. The lower the pKa value, the stronger the acid. Citric acid has three pKa values: 3.13, 4.76, and 6.40, indicating that it is a polyprotic acid (it can donate multiple protons). Tartaric acid also has two pKa values: 2.98 and 4.34. Comparing their pKa values, we see that citric acid is slightly stronger than tartaric acid.

Another way to compare their strengths is by examining acidity constants, expressed as Ka or pKa values, which are experimentally determined values that indicate the strength of an acid in a specific solvent. Citric acid has higher acidity constants for its first and second dissociation steps compared to tartaric acid, supporting the notion that it is generally stronger.

Lastly, it's important to note that the strength of an acid can also depend on the specific conditions, solvents, concentrations, and temperature in which it is tested. Therefore, the strength comparison can vary under different experimental conditions.