CHEM ,F.3 急!

Question

1.The hazard warning labels shoud be displayed on a bottle of chlorine is_________.

2.When a dry cobalt (2)chloride paper os placed on a sample of moist sodium chloride ,what will be observed?

A.The dry cobalt (2) chloride paper turns pink.
B.The dry cobalt (2) chloride paper turns blue.
C.Effervescence occurs.
D.There is no observable change.

Why?

Answer 1

i think is b
因為dry cobalt (2)chloride paper(無水氯化鈷(2)試紙)一遇到水就會變成blue
so 當 sample of moist sodium chloride placed on dry cobalt (2)chloride paper it will turn blue.

Answer 2

1.The hazard warning labels shoud be displayed on a bottle of chlorine is __Toxic__ .

2.A.The dry cobalt (2) chloride paper turns pink, because when the cobalt (II) chloride
paper react with water , it will turn to pink from blue.

Answer 3

1. toxic
2. A
Dry cobalt(II) chloride is blue. it will form hydrated cobalt(II) chloride, which is pink, when in contact with water in the moisture.

Answer 4

Q2
The answer is A
It is because dry cobalt chloride test paper in to a simple containing water.The paper turns from blue to pink.

2007-01-10 22:44:13 補充：
Q1The hazard warning labels shoud be displayed on a bottle of chlorine is_________.The answer is toxic.

Answer 5

is a.because dry cobalt(2)chloride paper is blue in colour.when H2O is placed on the paper .it will turn pink