IGCSE Chemistry Paper-1: Specimen Questions with Answers 78 - 80 of 99
Question number: 78
Question
A metal X exhibits following properties. Which possible metal can be X
- It is found in free state in nature.
- It is a very less reactive metal.
- It does not corrode easily.
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | Iron |
|
| b. | Gold |
|
| c. | Aluminium |
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| d. | Magnesium |
|
Answer
b.Explanation
Noble Metals are found as pure metals because they are unreactive and don’t combine with other elements to form compounds. Because they are so unreactive, they don’t corrode easily. This makes them ideal for jewellery and coins. Noble metals include copper, palladium, silver, platinum, and gold.
Metals from Top to Down
Metals in order of reactivity
Question number: 79
Question
What is a redox reaction?
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | Gain of electrons by a molecule, atom or ion. |
|
| b. | Loss of electrons by a molecule, atom or ion. |
|
| c. | Both a. and b. are correct |
|
| d. | Question does not provide sufficient data or is vague |
|
Answer
c.Explanation
The reactions in which oxidation and reduction takes place simultaneously are known as redox reactions. Loss of electrons by a molecule, atom or ion is oxidation whereas) Gain of electrons by a molecule, atom or ion is known as reduction.
Question number: 80
Question
What will be the pH of 0.10 M of HCl solution?
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | 2 |
|
| b. | 1 |
|
| c. | 4 |
|
| d. | 3 |
|
Answer
b.Explanation
as we know that therefore, So, pH = 1. Hence, pH of. 10 M HCL solution is 1.