The following are the steps involved in drawing Lewis structure of the polyatomic trisulfide anion
:
Total number of valence electrons = 
Resonance is not possible in this ion. The molecular geometry of the ion will be bent as there are two lone pairs and two bond pairs on the central atom.
Answer:
The Two reasons are :-
1. Combustion efficiency
2. Standardization of test conditions as non-luminous flame.
Explanation:
A luminous flame isn't suitable for heating as it gives out soot (A black powdery or flaky substance consisting largely of amorphous carbon, produced by the incomplete burning of organic matter)
Answer:
A.
Explanation:
Water was added to the reaction after the completion of the reaction so as to lower the solubility if the product in the solution therefore, the product can be precipitated out. On adding water the reaction moves in forward direction and more product is formed. (By Le Chatelier's principle). Thus, the precipitation occurs. Hence, option A is correct.
A solute is a substance that dissolves into another substance , and forms a solution.
When parallel rays exit a concave lens, the light rays are divergent.
The rays diverge or bend away from the axis it has been traveling upon entering the lens when it reaches the other side of the lens. These rays appear to have come from the same focal point before entering the concave lens. When these parallel rays are extended, it will be traced back to a single point of origin.