Chem 高手請答!

1. Which of the following color changes is correct for the reaction of
iron(II)ion and the rust indicator, potassium hexacyanoferrate(III)?

A.Yellow to green
B Yellow to
C Blue to green
D Green to blue

ans : B
我想問iron(II)ion本身係pale green 而rust indicator 會show blue 當個個位置rust 時, but 點解個ans 唔係D Green to blue??

2.Which of the following changes are observed when acdified potassium
dichromate solution is added to a test tube of cold ethanol?

(1)Orange colour turns to green
(2)Smell of vinegar ids detected
(3)The solution gets warmer

Ans: (1) and (3) only

我想問其實cold ge ethanol 會唔會同acdified potassium
dichromate solution react ga?? 呢個反應唔係要heat under reflux or
warm ga 咩??
但唔明點解隻colour of acdified potassium
dichromate solution 會變,,
但又冇變做acid wor同埋solution 點會無端端 gets warmer ??
plz explain!

3.1St starement:
Branched soapless detergent causes oxygen depletion in water bodies.
2 nd statement:
Foms produced by branched soapless detergent covers the surface of water
for a long time.

Ans: 兩個都correct and 2nd 係1 st ge explantion.
我想問oxygen depletion 唔係soapy detergent(biodegradable ) 形成咩?

4.Calcium carbonate is often added to soil. correct .
呢句 點解correct ,,唔係Caclium oxide or Calcium hydroxide 先add to soil 咩??

5.我想問除左con. nitric acid 之外,,
仲有邊d reagents commonly stored in brown bottles??
佢地仲有咩common ge 特性?

thz !!