Answer:
1) substance B
2) The amount of undissolved substance in Beaker A remains the same as it was before the experiment and still the same upon increasing the temperature which means A is not dissolved at all . In beaker B the substance was 50g before the experiment and started to decrease with the increasing of temperature wich means the substance is dissolving and it is soluble in water .
Step-by-step explanation:
As you can see both substances A and B were in the same mass 50g before the experiment .
Substance A did not react with the water and its amount still 50g for the rest of experiment so it does not dissolved .
But,
substance B was reacting with water so we can see its amount is decreasing with the increasing of temperature.