A science teacher performs an experiment using two elements.
- Element A is burned in oxygen and the gas produced is dissolved in water to form Solution X.
- Element B is burned in oxygen and the gas produced is dissolved in water to form Solution Y.
After testing with litmus paper, the following observations are recorded:
| Solution | Observation |
| X | Blue litmus turns red |
| Y | Red litmus turns blue |
Study the information attentively and answer the given questions:
1. Which observation provides direct evidence that the oxide formed from Element A is acidic? - .
2. Which of the following could be Element B? - .