(1)



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(2)


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(3ai)
(i) Litmus paper
(ii) Universal indicator paper
(iii) pH paper


(3aii)
Distilled water is free from impurities, dissolved salts, and ions (such as calcium, magnesium, or chloride ions) that may interfere with the reactions during analysis.

(3aiii)
(i) Smell or odor
(ii) Effects on litmus paper
(iii) Flammability


(3bi)
Sodium trioxocarbonate (IV) (Na?CO?) functions as a base because it reacts with acids to neutralize them, forming a salt, water, and carbon dioxide gas.

(3bii)
Silver trioxonitrate (V) (AgNO?) is light-sensitive and decomposes when exposed to light, releasing elemental silver and nitrogen oxides. Storing it in an amber-colored bottle protects it from light, preventing decomposition and maintaining its stability.