1)Which of the following substance cannot conduct electricity in solid state but can
do so in molten state?
A. silicon dioxide
B. hydrogen fluoride
C. magnesium fluoride
D. graphite
2)Calcium chloride does not conduct electricity is solid state because
A. it is not a metal.
B. it does not contain ions.
C. it does not possess charged particles.
D. its ions are not free to move.
3)Which of the following statements about sodium bromide is incorrect?
A. Sodium bromide has a high melting point.
B. When crystalline sodium bromide is dissolved in water, the ions are free to
move.
C. A solution of sodium bromide is electrically neutral.
D. Bromide ions present in sodium bromide have different chemical properties
from bromine.
Question 4:
Which of the following substances cannot conduct electricity in solid state but can
be electrolysed when molten?
A. sodium
B. zinc chloride
C. graphite
D. iodine
Chemistry!!!!!!Difficult Qs!!
2011-09-01 2:27 am
回答 (2)
2011-09-01 7:32 am
✔ 最佳答案
1) C. It is an ionic compound which cannot conduct electricity at solid state because it has no mobile ions, however, in molten state, it does.2) D. Same as question (1)
3) C. Sodium ions and bromine ions are not electrically neutral because the electron number is not as equal as the proton number. They carry +1 and -1 charge respectively.
4) B. It can be electrolyzed into zinc at cathode and chlorine at anode.
參考: Knowledge is power.
2011-09-01 9:57 am
1.
Liquid HF should be able to conduct electricity, owing to the auto-ionization of HF:
2HF <======> H(+) + HF2(-)
Surely C is the most appropriate one, but...
2011-09-01 01:57:29 補充：
3.
What does it mean by "electrically neutral"?
The overall charge of all ions in the solution is zero, which can imply electrical neutrality.
Liquid HF should be able to conduct electricity, owing to the auto-ionization of HF:
2HF <======> H(+) + HF2(-)
Surely C is the most appropriate one, but...
2011-09-01 01:57:29 補充：
3.
What does it mean by "electrically neutral"?
The overall charge of all ions in the solution is zero, which can imply electrical neutrality.
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