A sample of copper (ll) carbonate when heated in a hard glass tube, formed a black residue of copper (ll) oxide with the evolution of a colourless gas. Identify the colourless gas.
Important Questions on Question Bank
Solve the following crossword puzzle using the guidelines given in the table below:
Down:
1. The reaction which occurs in the presence of sunlight.
4. The process in which an atom in a molecule is replaced by another atom.
7. The process of splitting a substance into two or more substances.
8. The reaction occurring as
Across:
2. The new substance produced when two substances react.
3. The process in which two substances combine to produce a single substance.
5. The process in which coal burns to form carbon dioxide.
6. The process in which hydrogen from a compound is removed.
Match the substances in column A with their pH values in column B.
| A | B |
| (a) Lemon juice | (i) |
| (b) Tomato juice | (ii) |
| (c) Vinegar | (iii) |
| (d) Urine | (iv) |
| (e) Blood | (v) |
| (f) Lime water | (vi) |
Match the acids given in column A with their natural sources given in column B.
| A | B |
| (a) Tannic acid | (i) Red ants |
| (b) Formic acid | (ii) Curd |
| (c) Tartaric acid | (iii) Tea |
| (d) Lactic acid | (iv) Tomato |
| (e) Oxalic acid | (v) Tamarind |
Write Yes or No.
Can onion juice be used by a blind student to test whether a solution is acidic or basic?
