Question

In the given chemical equation 'A' stands for : Mg + 2A → MgCl2 + H2 A. H2SO4 B. HNO3 C. HCI D. HCO​

Answer 1

Answer:

Electric Potential is similar to flow of water from one end of a tube connected to a tank at a higher level to another tank at the other end of the tube at a lower level.

Charge flows from a point of higher potential to a point of lower potential.

For any charge, electric potential is the electric potential energy divided by the quantity of charge.

As an object is lifted against gravity, it gains gravitational potential energy which is proportional to the work done to raise the object against gravitational pull.

Similarly, an object gains some electric potential energy as it is moved against the electric field.

This energy is proportional to the amount of work done in moving the object from one point to another against the electric field. The electric potential is taken as zero at infinity.

POTENTIAL DIFFERENCE

The potential difference between two points in an electric circuit is defined as the amount of work in moving a unit charge from one point to the other point.

It is expressed as:

Potential difference = Work doneQuantity of charge moved

Potential difference, V = WQ

UNIT OF POTENTIAL DIFFERENCE

The SI unit of potential difference is volt.

The Potential difference between two points is said to be 1 volt if 1 joule of work is done in moving 1 coulomb of electric charge from one point to the other.

1V = 1 J C–1

Voltmeter: The potential difference is measured by means of an instrument called voltmeter whose terminals are connected across the points or parallel to the element whose potential is to be measured.rho, ρ, is quantitatively equal to the resistance R of a specimen such as a wire, multiplied by its cross-sectional area A, and divided by its length l; ρ = RA/l. The unit of resistance is the ohm. In the metre-kilogram-second (mks) system, t

Answer 2

'A' stands for C. HCI in the given chemical equation.

Explanation:

• This chemical reaction represents the reaction of magnesium ribbon with hydrochloric acid. It is an example of a chemical reaction in which a pure element reacts with an acid to form a salt of that element.
• In this chemical reaction, when magnesium(Mg) reacts with hydrochloric acid(HCl) the magnesium atoms substitutes(replaces) the hydrogen atoms in HCl to form Magnesium Chloride salt $(MgCl_{2} )$.
• This type of reaction is called Substitution reaction or single replacement reaction as one of the reactant atom substitutes with the other reactant.