Question

1. Na/ Nacl gives golden yellow colour when subjected to bonsen flame? 2. ZnO is qhite at low temp. but yellow at high temp.? expln both

Answer 1

1) it is a conclusion of flame test ,on directly heating several compounds or elements show different Colours Because each element has an exactly defined line emission spectrum, scientists are able to identify them by the color of flame they produce. For example, copper produces a blueflame, lithium and strontium a redflame, calcium an orange flame, sodium a yellow flame, and barium a green flame.etc
2)same ,at room temperature that point is not reached where it show the photo electric effect,change color but on heating electron release shows the formation of yellow color