Cambridge Secondary (7-9). Stage 7. MCE Science. Student Book - Unit 9: Chemical Reactions - Question 75

Hassan adds sodium to water in a beaker. The substances react violently to form sodium hydroxide and a colourless gas. He collects some of the gas in a test tube. He then puts a lighted splint into the test tube of gas and hears a ‘pop’ sound.

How does the pH value of the water in the beaker change? Explain your answer.