Physical Properties of Aldehydes and Ketones: Boiling point: The boiling point of methanal is -19o C and for ethanal it is +21o C. From this we can say that the boiling point of ethanal is close to room temperature. Generally the boiling point of aldehydes and ketones increases with increase in molecular weight.
In aldehydes, the carbonyl group has a hydrogen atom attached to it together with either a second hydrogen atom or, more commonly, a hydrocarbon group which might be an alkyl group or one containing a benzene ring. For the purposes of this section, we shall ignore those containing benzene rings.
Notice that these all have exactly the same end to the molecule. All that differs is the complexity of the other group attached. When you are writing formulae for these, the aldehyde group (the carbonyl group with the hydrogen atom attached) is always written as -CHO - never as COH. That could easily be confused with an alcohol. Ethanal, for example, is written as CH3CHO; methanal as HCHO. The name counts the total number of carbon atoms in the longest chain - including the one in the carbonyl group. If you have side groups attached to the chain, notice that you always count from the carbon atom in the carbonyl group as being number 1.
Answers & Comments
Verified answer
Answer:
Physical Properties of Aldehydes and Ketones: Boiling point: The boiling point of methanal is -19o C and for ethanal it is +21o C. From this we can say that the boiling point of ethanal is close to room temperature. Generally the boiling point of aldehydes and ketones increases with increase in molecular weight.
Explanation:
please make me brinalis
Answer:
Aldehydes
In aldehydes, the carbonyl group has a hydrogen atom attached to it together with either a second hydrogen atom or, more commonly, a hydrocarbon group which might be an alkyl group or one containing a benzene ring. For the purposes of this section, we shall ignore those containing benzene rings.
Notice that these all have exactly the same end to the molecule. All that differs is the complexity of the other group attached. When you are writing formulae for these, the aldehyde group (the carbonyl group with the hydrogen atom attached) is always written as -CHO - never as COH. That could easily be confused with an alcohol. Ethanal, for example, is written as CH3CHO; methanal as HCHO. The name counts the total number of carbon atoms in the longest chain - including the one in the carbonyl group. If you have side groups attached to the chain, notice that you always count from the carbon atom in the carbonyl group as being number 1.
Explanation:
CH3CHO
aldehyde
+21