Question

Structure of past perfect tense​

Answer 1

Answer:

Those substances whose smell (or odour) changes in acidic or basic solutions are called olfactory indicators. Onion and vanilla extracts are olfactory indicators. When a basic solution like sodium hydroxide is added to a cloth strip treated with onions (or onion extract), then the smell of onion vanishes.

Answer 2

Answer:

Those substances whose smell (or odour) changes in acidic or basic solutions are called olfactory indicators. Onion and vanilla extracts are olfactory indicators. When a basic solution like sodium hydroxide is added to a cloth strip treated with onions (or onion extract), then the smell of onion vanishes.

Answer 3

Answer:

Those substances whose smell (or odour) changes in acidic or basic solutions are called olfactory indicators. Onion and vanilla extracts are olfactory indicators. When a basic solution like sodium hydroxide is added to a cloth strip treated with onions (or onion extract), then the smell of onion vanishes.

Answer 4

Answer:

Those substances whose smell (or odour) changes in acidic or basic solutions are called olfactory indicators. Onion and vanilla extracts are olfactory indicators. When a basic solution like sodium hydroxide is added to a cloth strip treated with onions (or onion extract), then the smell of onion vanishes.

Answer 5

Answer:

Those substances whose smell (or odour) changes in acidic or basic solutions are called olfactory indicators. Onion and vanilla extracts are olfactory indicators. When a basic solution like sodium hydroxide is added to a cloth strip treated with onions (or onion extract), then the smell of onion vanishes.

Answer 6

Answer:

Those substances whose smell (or odour) changes in acidic or basic solutions are called olfactory indicators. Onion and vanilla extracts are olfactory indicators. When a basic solution like sodium hydroxide is added to a cloth strip treated with onions (or onion extract), then the smell of onion vanishes.