A student is testing substance P & Q as shown. The result turns the Universal Indicator blue. Can you predict substance P & Q?
Any ammonium salt and sodium hydroxide! The reaction between both will cause formation of ammonia, that causes UI to turn blue.
Between zinc oxide and nitrogen dioxide, which can be used to neutralise an acidic solution?
Magnesium oxide! We need alkaline to neutralise acidic solution. Nitrogen dioxide is related to acid rain, remember?
Kifayat arm's stings from the bite of wasp as it slightly alkaline. Which substance should be used to neutralise the bite?
Lime juice. As the bite is already alkaline, something acidic will neutralise it. Why can't Kifayat use battery acid?
Bibi wanted to prepare copper sulfate by reacting insoluble copper oxide to sulfuric acid. Which letter represents the best method?
B. The insoluble base will be added until it no longer reacts, and later filtered to removed unreacted base. Lastly, it is cooled down to crystallise salt.
True or false: carbon dioxide gas relights a glowing splint.
False, oxygen relights glowing splint. How do you test carbon dioxide? What would be the positive result?
Aqueous sodium hydroxide is added to solid X and the mixture is heated. A blue precipitate is formed and an alkaline gas is given off. Which ions are present in X?
Copper ions and ammonium ions! Copper forms the blue coloured complex while ammonium gives off ammonia - an alkaline gas.
Reaction involving sodium is shown in the figure. Which reaction in the figure does not involve the formation of a base/alkali?
C as it forms sodium chloride as product. Sodium chloride is not a base/alkali, it is neutral!
Cabbage grows best when the soil when the environment is slightly acidic. Based on the graph shown, which letter represents best condition for cabbage to grow?
D, the pH is not too low and it's close to neutral!
Experiment was done to identify anion in X salt. Dilute nitric acid was added and the solution forms colourless bubbles. Can you predict the anions?
It's the carbonate ions, the bubbles formed is the carbon dioxide! Can you do further test to make sure it is carbon dioxide?
