Discussion
Which one of the following minerals melts incongruently ?
Answer: B
Of these, pyrite melts incongruently.
A mineral melts incongruently when, on heating, it breaks down into a liquid and a different solid instead of a liquid of its own composition. Pyrite, FeS2, does not melt as such: at about 743°C it breaks down to pyrrhotite and a sulphur-rich liquid.
Forsterite, anorthite and quartz melt congruently at atmospheric pressure, each to a liquid of its own composition (at about 1890°C, 1553°C and 1713°C respectively). The textbook example of a silicate melting incongruently, enstatite (to forsterite plus liquid), is not among the options.
No comment is present. Be the first to comment.
Loading…
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