Answer: a
Explanation: because an Arrhenius acid is a compound that increases the H + ion concentration in aqueous solution. An Arrhenius base is a compound that increases the OH − ion concentration in aqueous solution.
Answer is (4) - Pb.
According to the reactivity series of elements
- the elements which are above the hydrogen are more reactive than hydrogen.
- the elements which are below the hydrogen are less reactive than hydrogen.
Among the given choices, only Pb is placed above the hydrogen in the reactivity series and rest are below the hydrogen.
Hence, Pb is more active than hydrogen.
The answer to this question would be: alkaline earth metal
Alkali earth metal is the second column group of the periodic table. In this group, the element has 2 extra electrons in their outer cells. That is why most of this metal has 2+ charge.
Their neighbor is the alkali metal which was the first column of the periodic table. The name is similar so don't confused and mix them each other.
Answer:
1. B, D,
2.A, F
Explanation:
1. According to the law of conservation of mass, In a course of chemical reaction, matter can neither be created nor destroyed but can be changed from one form to another. This means the amount of matter at the begining and ending of a reaction must be thesame.
2. Chemical reaction is not easily reversible. when gas is produced, provided the reaction system is an open system, the gas cannot be recovered and the reactants cannot be recovered from the products. likewise color change are attributed to chemical reaction
