All India Engineering / Architecture Entrance Examination (AIEEE)

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AIEEE 2008 Chemistry

Q. 10. Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly?

1. Metal sulphides are less stable than the corresponding oxides.
2. CO₂is more volatile than CS₂.
3. Metal sulphides are thermodynamically more stable than CS₂.
4. CO₂is thermodynamically more stable than CS₂.

Sol:

Hence, CO₂ is more stable than CS₂ while Ms are more stable than MO.

Q. 11. Four species are listed below:

Which one of the following is the correct sequence of their acid strength?

(1) (i) < (iii) < (ii) < (iv) (2) (iii) < (i) < (iv) < (ii) (3) (iv) < (ii) < (iii) < (i) (4) (ii) < (iii) < (i) < (iv)

Sol: The increasing order of acidic strength is

Q. 12. Which one of the following constitutes a group of the isoelectronic species?

Sol: Isoelectronic species have same number of electrons