Based on the following results;

Quantity I/units	Rough	First	Second	Third
Titre/mL	18.2	18.3	18.2	18.2

Table 1: Standardisation

T1	16.4	16.1	16.2	16.1
T2	27.2	27.0	27.1	27.1

Table 2: Artificial Water Sample

T1	0.0	0.0	0.0	0.0
T2	4.0	3.9	4.0	3.9

Table 3: Water from the River

Calculate the concentrations of carbonate and hydroxide in the solution supplied and the standard deviations of your measurements. Use the expressions:

No. of moles of NaHCO3 (T2-T1) and No. of moles of NaOH (2T1-T2), where T2 is the volume of acid required for the two end points and T1 the volume for the first end point. If the molarity of sulphuric acid is MH, the unknown molarities of carbonate and hydroxide, MC and MOH are given by: [Mc x 25]/[MH x (T2 - T1)] = 2/1 and [MOH x 25]/[MH x (2T1 T2)] = 2/1