<u>Answer:</u> The balanced chemical equation is written below.
<u>Explanation:</u>
Double displacement reaction is defined as the reaction in which exchange of ions takes place.

When sodium permanganate reacts with iron (III) chloride, it leads to the production of sodium chloride and iron (III) permanganate.
The chemical equation for the reaction of sodium permanganate and iron (III) chloride follows:

By Stoichiometry of the reaction:
3 moles of aqueous solution of sodium permanganate reacts with 1 mole of aqueous solution of iron (III) chloride to produce 1 mole of solid iron permanganate and 3 moles of aqueous solution of sodium chloride
Hence, the balanced chemical equation is written above.
Scientists use special tools to do their work. They gather data, or information, as they seek to learn about the world. In order to solve problems they must record data that is accurate and organized. This is an important part of the scientific method.
Answer:
Gold
Explanation:
We are given that
Mass of sample ,m=385 g
Volume ,V=20mL
We have to find the coin is gold or yellow brass.
We know that
Density=
Using the formula



Density of coin=19.3g/mL
Density of gold=19.3g/mL
Hence, the coin is gold.
Answer:
51:49 is the ratio of female participants to male participants.
Explanation:
Percentage of females in the race = 51 %
Percentage of males in the race = 100% - 51 % = 49%
Total participants in race = 400
Number of women participants = 
Number of men participants = 
Ratio of female participants to male participants :

Answer:
Neutralization
Explanation:
When an acid react with base it form the salt and water. The reaction is also called neutralization reaction because both neutralize each other.
In neutralization reaction equal amount of acid and base react to neutralize each other and equal amount of water and salt are formed. When pH does not reach to 7 its means there is less amount of one of reactant which is not fully neutralize.
Neutralization reactions are also used as first aid. For example when someone is dealing with HCl for cleaning purpose of toilet and get touched. It is advised to neutralize it with soap, milk or egg white.
Example:
Hydrochloric acid when react with the sodium hydroxide, a salt sodium chloride and water are formed.
Chemical equation:
HCl + NaOH → NaCl + H₂O
Titration:
Neutralization reactions are also used to determine the concentration of solution. Titration is a quantitative technique in which acid or base is gradually added into the solution whose concentration is to be determine until the neutral point is reached.