Bromocresol green acts as an acid-base indicator. At pH values below 3.8, it appears yellow. At pH values above 5.4, it appears blue. In the range between these values, it is green. Bromocresol green is introduced into the aqueous solution produced when the chloride of element T is added to water. The solution turns yellow. If an excess of the solid oxide of element U is added slowly to this yellow solution, the indicator changes to green and then blue. Which row could be used to identify element T and element U?
- AElement T: silicon; Element U: sodium
- BElement T: silicon; Element U: phosphorus
- CElement T: magnesium; Element U: sodium
- DElement T: magnesium; Element U: phosphorus