The correct answer is option a, that is, they produce ions when dissolved in water.
The acids and bases refer to the chemical components, which reacts with water. The molecules of acids dissociate to give hydrogen ions to water, while the bases dissociate to provide hydroxide ions to the water, or that takes hydrogen ions from water and leave the hydroxide ions behind.
If an emergency vehicle passes you in traffic, just as it passes you the pitch of the siren changes as it approaches, the siren’s pitch sounds higher than when it is moving away from you.the frequency increases as the siren is moving toward you, and decreases as it is moving away, is correct
This change is a common physical demonstration of the Doppler effect.
<h3>What is Doppler effect ?</h3>
This effect refers to the increase in the frequency of sound, as the source and observer move toward (or away from) each other.
The effect causes the sudden change in pitch noticeable in a passing siren.
Hence Option (B) i.e, the frequency increases as the siren is moving toward you, and decreases as it is moving away, is correct
Learn more about Doppler' effect here ;
brainly.com/question/27507962
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