No, purple flames are not necessarily the hottest. Flame color is related to the temperature of the flame, but other factors can also affect flame color, such as the chemical composition of the fuel and the presence of impurities.
In general, the temperature of a flame is indicated by its color, with the hottest flames being blue and white. The blue flame is usually the hottest, with temperatures ranging from 1,400 to 1,800 degrees Celsius (2,550 to 3,270 degrees Fahrenheit), while white flames can reach temperatures as high as 2,500 degrees Celsius (4,532 degrees Fahrenheit).
Purple flames can indicate the presence of certain elements, such as potassium or copper, and their temperature can vary depending on the conditions in which they are produced. However, in general, purple flames are not as hot as blue or white flames.
It's worth noting that flame temperature can be affected by many factors, such as the type of fuel, the amount of oxygen present, and the heat transfer properties of the surrounding materials. Therefore, flame color should not be relied upon as the sole indicator of flame temperature.