I believe it is a physical change.
Answer:
Explanation:
a ) Benzoic acid is formed . In any alkyl benzene derivative , potassium permanganate reacts to form carboxylic acid . It oxidises side chains to carboxylic acid .
C₆H₅CH₃ + 0 = C₆H₅COOH + H₂O
O is provided by KMnO₄
b ) In this reaction isophthalic acid is formed .
C₆H₄(CH₃)₂ +O = C₆H₄(COOH)₂
c)
4-Propyl-3-t-butyltoluene
In this oxidation , three side chains of ring are 1 ) 1-methyl 2 ) 3- butyl 3 ) 4 propyl .
The methyl and 4 - propyl groups are oxidised to di- carboxylic acid and 3 butyl group remains intact ( unoxidised )
Answer:
3Fe2O3 + H2 --> 2Fe3O4 + H2O
It is so because warm air is lighter than cold air. Cold air means the molecules are not moving as much, so they will feel like sticking together and will not jump around as molecules in warm air will(higher temp. means higher KE). Think of a solid, colder solids are much heavier than warmer ones(think of ice-starts melting).
