Answer:
a

b

Explanation:
Generally the force of attraction between this two irons is mathematically represented as
![F = \frac{k * [Q_{Li} ] * [Q_{O} ] }{ r^2}](https://tex.z-dn.net/?f=F%20%3D%20%20%5Cfrac%7Bk%20%2A%20%20%5BQ_%7BLi%7D%20%20%5D%20%2A%20%5BQ_%7BO%7D%20%20%5D%20%20%7D%7B%20r%5E2%7D)
Here k is known as the proportionality constant with value 
substituting -2 for
i.e the charge on oxygen , +1 for
i.e the charge on Lithium and
for r
So


Generally the force of repulsion will be the magnitude but different direction to the force o attraction
So Force of repulsionn is

Answer: The correct option is Option b.
Explanation:
Power is defined as the rate of work done by an object.
Mathematically,
.....(1)
And work done is the product of force exerted on the object times the displacement covered by that object.
Mathematically,

Putting this value in above equation, we get:

where,
P = power = ?W
F = Force exerted = 10N
s = Displacement = 400cm = 4m (Conversion factor: 1m = 100 cm)
t = Time taken = 8s
Putting values in above equation, we get

Hence, the correct option is Option b.
Given:
The balanced chemical reaction of the synthesis of phosphorus trichloride:
2P + 3Cl2 ===> 2PCl3
Initial amount of phosphorus = 15 grams
The amount of product produced from 15 grams of phosphorus:
15 grams / 31 g/mol * (2/2) = 66.46 grams PCl3
The amount of chlorine is 44.31 grams, nearest to 45 grams.