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Sodium hydroxide reacts with hydrochloric acid - OCR Gateway - GCSE Chemistry Combined Science - Question 16 - 2018 - Paper 1
Question 16
Sodium hydroxide reacts with hydrochloric acid. Sodium chloride and water are made. (a) Write a word equation for this reaction. (b) A student adds 5cm³ of hydroc... show full transcript
Worked Solution & Example Answer:Sodium hydroxide reacts with hydrochloric acid - OCR Gateway - GCSE Chemistry Combined Science - Question 16 - 2018 - Paper 1
Step 1
Step 2
Step 3
Describe the pattern of the highest temperature reached during experiments A to C.
Answer
The temperature increases from experiment A to C. Specifically, as the volume of hydrochloric acid (HCl) increases, the highest temperature reached also rises.
- Experiment A: 30.2 °C
- Experiment B: 35.0 °C
- Experiment C: 37.2 °C
This indicates that more HCl leads to a higher temperature.
Step 4
Describe the pattern of pH at the end of the reaction for experiments A to D.
Answer
The pH values generally decrease as the volume of hydrochloric acid (HCl) increases.
For experiment A, the pH is 12.0, indicating a basic solution. As we move to experiments B, C, and D (with more HCl), we can infer that the pH will also decrease, approaching neutrality or acidity.
This suggests that the reactions are becoming more balanced as acid is added.