Question

Explain the following statements?
1. State the relation between hydrogen ion concentration of an aqueous solution and its pH.
2. An aqueous solution has a pH value of $ 7 $ . Is this solution acidic, basic or neutral?
3. Which has a higher pH value, $ 1M{\text{ HCl or 1M NaOH}} $ solution?
4. Tooth enamel is one of the hardest substances in our body. How does it undergo damage due to eating chocolates and sweets? What should we do to prevent it?
5. How do $ ({H^ + }) $ ions exist in water?

Answer 1

Hint :To solve this question we have to recall the basic principle and rules of pH, just consider molarity also. By the standard rules, the solution having the pH below than $ 7 $ is considered to be acidic, whereas, at the $ 7 $ , it is neutral and pH above $ 7 $ is considered to be basic.

Complete Step By Step Answer:
pH is the logarithm of reciprocal of hydrogen ion concentration in gram moles per litre.
Or in the equation form, it is written as -
 $ pH = - \log ({H_3}{O^ + }) $
Thus, we can say that, if the pH. of the solution increases then, the hydrogen ion concentration decreases or vice –versa.
As, mentioned in the hint section, the standard rules of the determination of pH, so an aqueous solution with pH $ 7 $ , would be a neutral solution.
 $ 1M{\text{ HCl or 1M NaOH}} $ - This is a pure concept based question, since we know the solutions having pH greater than $ 7 $ , is basic in nature. So $ 1M{\text{ NaOH}} $ , will have higher pH than $ 1M{\text{ HCl}} $ as the former is basic in nature.
Enamel destruction – No matter, how hard the substance is microorganisms are capable of degrading it by converting it into simple acids. To prevent enamel and tooth damage one should properly brush their teeth twice a day.
 $ ({H^ + }) $ Ions existence – since $ ({H^ + }) $ molecules are unstable in mono form. So they react with water to form $ ({H_3}{O^ + }) $ ions.
As, $ {H^ + } + {H_2}O \to {H_3}{O^ + } $

Note :
You need to protect your enamel from microbes by brushing them twice a day but make sure that you don’t push your brush too hard on the tooth enamel because this process also withers down the enamel.