the weatherhat happens if the temparature dropps below 50.c
It would be easier for living things to survive. If the organism is warm-blooded, they would have to utilize adaptations to remove excess heat, via sweating, or with larger surface area to volume ratios in their bodies. They would have to use behaviors to come out in the evening when the sun was not out to help them survive these temperatures. Therefore, if the temperatures drop, they would have an easier time of existing in that environment.
It gets substantially cooler, for one thing. 50 degrees Celsius is pretty high when converting to Fahrenheit, far and above what we would call habitable temperature. In some areas of the United States, around the Grand Canyon area, in the suimmer, heat indexes reach around 115 degrees Fahrenheit. So the temperature you are describing, at least for the time being, is unrealistically high.
50 degrees Celsius is equal to 122 degrees Fahrenheit. Given that 122 degrees Fahrenheit is a very high temperature, a drop in temperature would make survival for plants and animals much easier. The Sahara Desert can get to be 40 degrees Celsius or higher. Therefore, some life can exist in temperatures that high.
I assume you can't really be talking about weather here since 50 C would be awfully hot. So I wonder what you are really asking about. Can you clarify your question? Are you asking about some sort of chemical reaction? Did you make a mistake in the temperature you're asking about? Anyway, please clarify.
In some major cities of Pakistan, the temperature stays around 115 degrees Fahrenheit for around week to 2 weeks. Some times the temperatures are higher than 115 for a couple of days. In some small towns it goes beyond 50C/122F and people are still living there.
Basically, its a matter of getting climatised. People living in palces with very high temperature survive those temperatures whereas for others it can be a matter of life and death.