The species Ar, K+ and Ca2+ contain the same number of electrons. In which order do their radii increase?
1. Ar < K+ < Ca2+
2. Ca2+ < Ar < K+
3. Ca2+ < K+ < Ar
4. K+ < Ar < Ca2+
Which of the following biologically important ions is also a constituent of the sodium pump?
1. Ca2+
2. Mg2+
3. K+
4. Fe2+
"Metals are usually not found as nitrates in their ores". Out of the following two (I and II) reasons which is/are true for the above observation?
| I: | Metal nitrates are highly unstable. |
| II: | Metal nitrates are highly soluble in water. |
2. I and II are False
3. I is False but II is True
4. I is True but II is False
Solubility of alkaline earth metal sulphates in water decreases in the sequence:
1. Mg > Ca > Sr >Ba
2. Ca > Sr > Ba > Mg
3. Sr > Ca > Mg > Ba
4. Ba > Mg > Sr > Ca
A pair among the following have nearly the same atomic radii:
(Numbers in the parenthesis are atomic numbers).
| 1. | Ti (22) and Zr (40) | 2. | Zr (40) and Nb (41) |
| 3. | Zr (40) and Hf (72) | 4. | Zr (40) and Ta (73) |
Which of the following processes does not involve the oxidation of iron?
| 1. | Rusting of iron sheets |
| 2. | Decolourisation of blue CuSO4 solution by iron |
| 3. | Formation of Fe(CO)5 from Fe |
| 4. | Liberation of H2 from steam by iron at high temperature |
| 1. | \(\mathrm{CO}_3^{2-}, \mathrm{SO}_3^{2-} \) | 2. | \(\mathrm{ClO}_3^{-}, \mathrm{CO}_3^{2-} \) |
| 3. | \(\mathrm{SO}_3^{2-}, \mathrm{NO}_3^{-} \) | 4. | \(\mathrm{ClO}_3^{-}, \mathrm{SO}_3^{2-}\) |
2. Is a reducing agent
3. Is soluble in water
4. Is used as a food-preservative
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