Question

Which of the following is true for compounds?

Answer 1

They can be created by chemical reactions.

Compounds have varying properties, depending on the compounds they are made from, and are created by chemical reactions.

Answer 2

Answer: The correct option is that the compounds are created by chemical reactions.

Explanation:  

Option 1: Elements combine chemically in a specific ratio to form compounds. They can't be separated by physical methods like filtration. For example, $H_2O$ is made up 2 H-atoms and 1 O-atom. When we filter water through normal filtration, we do not obtain H-atom and O-atom separately, but we get combined form of hydrogen and oxygen atom that is $H_2O$.

Option 2: Compounds are formed when two or more elements combine chemically.

$2H_2(g)+O_2(g)\rightarrow 2H_2O(l)$

Option 3: Compounds can have more than two types of elements. For example, In $CaCO_3$, 3 elements are present - Calcium(Ca), Carbon(C), Oxygen(O).

Option 4: Compounds formed have different properties from one another. There can be difference in physical properties as well as chemical properties. For example, $H_2O$ (water) and $CaCO_3$ (calcium carbonate) are two compounds. Water is present in liquid state and calcium carbonate is present in solid state. Hence, it showed that all the compounds cannot have same properties.