Answer to Question #64686 in General Chemistry for Laiba Sabir

Question

Three solution bottles have lost their labels. The soloutions are potassium chloride ,nitric acid and sodium hydroxide. Describe how you would use Universal indicator to identify each solution and re-label each bottle

Answer 1

Solution: A universal indicator is a pH indicator that exhibits several smooth colour changes over a pH value range from 1 to 14 to indicate the acidity or alkalinity of solutions. The potassium chloride in water solution is dissociated into potassium ion (K+) and chloride ion (Cl-) that do not change a pH level. However, the Universal indicator will be green. The nitric acid is dissociated into nitric ion (NO3-) and hydrogen ion (H+) that lead to decrease a pH. So, the Universal indicator will be red or yellow (depending on acid concentration). The sodium hydroxide is dissociated into sodium ion (Na+) and hydroxide ion (OH-) that lead to increase a pH. Therefore, the Universal indicator will be blue or purple (depending on base concentration).

Answer: So, if drop the Universal indicator in each bottle, in the potassium chloride it turns green, in the nitric acid it turns red or yellow and in the sodium hydroxide it turns blue or purple.