Answer:
the SI base unit of electrical current
Answer:

Explanation:
m = Mass attached to spring = 14 kg
g = Acceleration due to gravity = 
x = Displacement of spring = 
k = Spring constant
The force balance of the system is given by

The spring constant for that spring is
.
The type of reaction that occurred in the test tube is ACID BASE REACTION.
Acid base reaction is a type of chemical reaction in which an acid and a base react together to form salt and water molecules. It is also known as neutralization reaction. For the question given above, the applicable chemical reaction is as follows:
HF + NaOH = NaF + H2O
From this chemical reaction, it can be seen that, hydrogen fluoride, which is a weak acid react with sodium hydroxide which is a strong base to produce sodium fluoride, which is a salt and a molecule of water.