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How to calculate n or x in titration/chemistry calculations(urgent)

hey guys
I need help on how to calculate x or n in a compound , specifically this question:4. Succinic acid has the formula (CH2)n(COOH)2 and reacts with dilute sodium hydroxide as follows: (CH2)n(COOH)2 + 2NaOH (CH2)n(COONa)2 + 2H2O
2.0 g of succinic acid were dissolved in water and the solution made up to 250 cm3. This solution was placed in a burette and 18.4 cm3 was required to neutralise 25 cm3 of 0.1 moldm-3 NaOH. Deduce the molecular formula of the acid and hence the value of n.


If a step to step method on how to calculate these types of questions is given, that would be much appreciated! Thanks :smile:
I can't give a step-by-step method because every question will give you different data. However, the key is to make sure you get the number of moles to match. In this case, the number of moles of succinic acid is half the moles of NaOH (this can be seen by the symbol equation).

Moles of NaOH = 0.1*0.025 = 0.0025mol

Concentration of succinic acid = moles/volume = 0.00125/0.0184 = 0.0679 mol/dm^3

Moles of succinic acid in total 250cm^3 solution = concentration * volume = 0.0679*0.25 = 0.0170 mol

Molar mass of acid = mass/mol = 2/0.0170 = 117.76, which is approximately 118.

Mr of (COOH)2 = 90

118-90 = 28

Mr of CH2 = 14

28/14 = 2, hence n=2

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