Answer: 4.
and 
Explanation:
a) The given reaction is 
As the mass on both reactant and product side must be equal:


As the atomic number on both reactant and product side must be equal:



b) 
Total mass on reactant side = total mass on product side
15 =15 + x
x = 0
Total atomic number on reactant side = total atomic number on product side
8 = 7 + y
y = 1

The amount of energy in molecules of matter determines the state of matter. Matter can exist in one of several different states, including a gas, liquid, or solid state. ... A gas is a state of matter in which atoms or molecules have enough energy to move freely.
It is going to be reaction of neutralization, and water and salt will be formed. If acid and base are strong, the reaction of the solution should become neutral.
Answer:
D.Salad
Explanation:
A mixture is a substance that combines two or more substance that are physically combined. A mixture can be easily seperated by a physical means . A mixture is the combination of various substances that are not chemically combined .Examples of mixtures are cake and salad . The cake contains various substances like egg, flour and sugar. This mixture can be easily separated into it individual entities by a physical means .
Base on the option the only mixture among the option is salad . Salad is a a mixtures that combines substances like tomatoes , fruits and vegetable. The individual substances that makes up the salad can be easily separated.
Sugar is a compound . Water is a compound as it contains two elements and potassium is an element.