Chemical changes are considered unseen because they occur at the atomic level, changing the actual structure of the thing.
B3+ is isoelectronic with helium.
Isoelectronicity is the phenomenon whereby two or more molecular entities have the same number of electrons or similar electronic configuration regardless of the nature of the elements that are involved.
In the question given above, helium and B3+ have the same number of electrons. Helium has two electrons. Boron has five electrons but it has given away three of the electrons [that is why it has a charge of +3] and it now has only two left.
PH (potential of hydrogen) is a numeric scale that is used to show the acidity or basicity of an aqueous solution. It tells how acidic or alkaline a substance is . The pH values ranges from 0 to 14, such that acidic solutions have values between 1 to 6.9 with most acidic having a pH value of 1 and those that are basic have values from 7.1 to 14, with most acidic having a value of 14. Acidic compounds contain replaceable hydrogen ions while basic compounds contain hrdroxyl ions. In this case, a coke has a pH of 3.5 (acidic) which means that it has an excess of hydrogen ions (H+) and would be called an acid.
Answer:
<h2>D) clapping hands </h2>
Explanation:
hope it's helpful
Answer:
True
Explanation:
The physical changes are reversible in most cases and these changes are not the chemical changes which means that it is only the change in its state not in their nature. Just take the example of water, on cooling it becomes solid and change in color can be seen which is white in solid form and colorless in liquid form. This is also reversible and is a physical change. This means that physical changes can be identified at macroscopic level. Hence the answer is true.
