Chem mc 3題 help!!

1)C.(2)&(3)only
Heating a cooking oil with sodium hydroxide solution can produce soapy detergent, but not soapless detergent. The other statements are the common properties of detergent.
2)
A.ethane and ethene
Incorrect. Both ethane and ethene will not react with acidified potassium dichromate solution(ethene can oxidized by acidified potassium permanganate, but not potassium dichromate)

B.ethanol and propan-1-ol
Incorrect. Both ethanol and propan-1-ol can reduce acidified potassium dichromate solution and turn it from orange to green

C.sodium carbonate and sodium hydrogencarbonate
Incorrect. Carbonate and hydrogencarbonate has is not a reducing agent

D.sodium sulphite and sodium sulphate
Correct. sodium sulphite can reduce acidified potassium dichromate solution and turn it from orange to green but sodium sulphate cannot
3)C.methyl methanoate
Alkanol and alkanoic acid with low carbon number(below 6) is soluble in water. Sodium methanoate is an ionic compound, so it is soluble.
Methyl methanoate is an ester. It is insoluble in water

Q.3 is problematic. There is no answer because all the four compounds are soluble in (or miscible with) water.

2009-01-18 22:12:15 補充：
Among all esters, methyl methanoate (the smallest ester, which is also named as methyl acetate) is the only one that is miscible with water. At room temperature, methyl methanoate has a solubility of 25% in water. At elevated temperature, its miscibility with water is much higher.