Chemistry
Assertion (A): Water is added to acids to dilute them.
Reason (R): The addition of water to acids is a highly exothermic reaction. Splashes of acid solution may come in contact with skin and container may also break.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
A is false but R is true.
Explanation — Acids are diluted by adding acid to water, not by adding water to acid. The goal is to reduce the concentration of hydrogen ions (H⁺) in solution safely. Hence the assertion (A) is false.
Reason (R) is true because water is not added to acid as it is an exothermic process and in this process so much heat is produced that splashing of acidic solution may occur, also the container may break which can be fatal to the person.
Related Questions
Assertion (A): Acids have a pH of more than 7.
Reason (R): Acids produce hydronium ions as the only positively charged ion in solution.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Iron (III) chloride is stored in a moisture proof container.
Reason (R): Iron (III) chloride is hygroscopic in nature.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
M is an element in the form of powder. M burns in oxygen and the product obtained is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences.
(a) If M is a metal, then the litmus will turn ……………
(b) If M is a non-metal, then the litmus will turn ……………
(c) If M is a reactive metal, then …………… will be evolved when M reacts with dilute sulphuric acid.
(d) If M is a metal, it will form …………… oxide, which will form …………… solution with water.
(e) If M is a non-metal, it will not conduct electricity unless it is in the form of ……………
Select the word/s given below which are required to correctly complete the blanks — [ammonia, ammonium, carbonate, carbon dioxide, hydrogen, hydronium, hydroxide, precipitate, salt water] :
(i) A solution M turns blue litmus red, so it must contain (i) …………… ions ; another solution O turns red litmus blue and hence, must contain, (ii) …………… ions.
(ii) When solution M and O are mixed together, the products will be (iii) …………… and (iv) …………… .
(iii) If a piece of magnesium was put into a solution M,(v) …………… gas would be evolved.