Discussion
Consider the following statements :
Statement-1 : The ratio of Ni : Mg is highest in early formed crystals like olivine and shows a steady decline in late formed minerals.
Statement-2 : The nickel ion has essentially the same radius as magnesium.
Which of the following is correct with respect to the above statements ?
Answer: B
The answer is Both statements are true and statement-1 is not the correct explanation of statement-2.
Statement-1 is true: nickel enters olivine readily, so the Ni : Mg ratio is highest in the earliest crystals and falls steadily in later minerals and residual liquids. Statement-2 is also true: the Ni2+ ion (about 0.69 Å) is very close in size to Mg2+ (about 0.72 Å), so it substitutes for magnesium.
The causal link runs the other way: the similar radius (statement-2), together with nickel's stronger preference for the olivine site, explains the early concentration of nickel (statement-1). Statement-1 does not explain statement-2, so option A, which claims it does, is wrong, and the options calling either statement false are wrong too.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development