A 0.05 M solution of sodium carbonate (Na2CO3) was prepared and then used to find the concentration of a hydrochloric acid (HCl) solution by titration - Leaving Cert Chemistry - Question 2 - 2018
Question 2
A 0.05 M solution of sodium carbonate (Na2CO3) was prepared and then used to find the concentration of a hydrochloric acid (HCl) solution by titration. Some pieces o... show full transcript
Worked Solution & Example Answer:A 0.05 M solution of sodium carbonate (Na2CO3) was prepared and then used to find the concentration of a hydrochloric acid (HCl) solution by titration - Leaving Cert Chemistry - Question 2 - 2018
Step 1
a) Name the pieces of apparatus A, B and C.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A: volumetric flask
B: burette
C: pipette
Step 2
b) Which piece of apparatus, A, B or C, was used:
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
(i) in making up the 0.05 M solution of Na2CO3: A, volumetric flask
(ii) to measure 25.0 cm³ of the Na2CO3 solution: C, pipette
(iii) to measure the hydrochloric acid in each titration: B, burette
Step 3
c) Identify one of these pieces of apparatus that was rinsed again with a second liquid.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The burette (B) was rinsed with the hydrochloric acid solution.
Step 4
d) Explain the underlined term.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A standard solution is a solution of known concentration that is used for titrations to ensure consistency in results and accurate calculations.
Step 5
e) Name a suitable indicator for use in the titrations.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Methyl orange
The colour change observed at the end point was from yellow (orange) to red (pink).
Step 6
f) Calculate the concentration of the HCl solution.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Using the volumes from the table:
Rough Titration Volume = 22.6 cm³ = 0.0226 L
Moles of Na2CO3 = 0.05×0.025=0.00125 moles
From the reaction,
2 moles of HCl react with 1 mole of Na2CO3.
Moles of HCl = 2×0.00125=0.0025 moles
Concentration of HCl = rac{0.0025 \text{ moles}}{0.0226 \text{ L}} \approx 0.1106 M
Join the Leaving Cert students using SimpleStudy...
