IGCSE Chemistry Paper-1: Specimen Questions with Answers 3 - 4 of 99
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Question 3
Question MCQ▾
An aqueous solution of the organic compound methylamine has a pH > 7. What can be said?
Choices
| Choice (4) | |
|---|---|
a. | It neutralises an aqueous solution of sodium hydroxide. |
b. | It reacts with hydrochloric acid to form a salt. |
c. | It turns blue litmus red. |
d. | It reacts with copper (II) carbonate to give carbon dioxide. |
Answer
b.Explanation
pH greater then 7 means that the solution is either basic or alkaline in nature. When methylamine reacts with HCL , following reaction takes place:
H3CNH2 + HCl ⇾ H3CNH3 + Cl
H3CNH3 formed in the reaction is known as N-methyl ammonium chloride, which is a salt.
Question 4
Question MCQ▾
Which statement will be true in regard to phosphorus (P, atomic no = 15) and Arsenic (As atomic no = 33) :
Choices
| Choice (4) | |
|---|---|
a. | They will have same amount of electronegativity |
b. | Arsenic is more electronegative then Phosphorus. |
c. | Phosphorus is more electronegative then Arsenic. |
d. | All of the above |
Answer
c.Explanation
Phosphorus is more electronegative then Arsenic. On moving down in a group, the number of shell increases and the valance electrons move away from the nucleus and the effective nuclear charge decreases. This decreases the attraction between the nucleus and the electrons hence decreasing electronegativity.