Home
Class 11
CHEMISTRY
Assertion : Soluable fluoride is often a...

Assertion : Soluable fluoride is often added to drinking water to bring its concentration up to 1 ppm.
Reason : `F^(-)` ion concentration above 2 ppm causes brown mottling of teeth.

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

If both assertion and reason are true but reason is not the c orrect explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Text Solution

AI Generated Solution

The correct Answer is:
To analyze the assertion and reason provided in the question, we will break down the statements and evaluate their validity step by step. ### Step 1: Understand the Assertion The assertion states that soluble fluoride is often added to drinking water to bring its concentration up to 1 ppm (parts per million). **Evaluation**: This statement is true. Fluoride is added to drinking water in controlled amounts to help prevent dental cavities. A concentration of around 1 ppm is considered beneficial for dental health. ### Step 2: Understand the Reason The reason states that fluoride ion concentration above 2 ppm causes brown mottling of teeth. **Evaluation**: This statement is also true. When fluoride levels exceed 2 ppm, it can lead to dental fluorosis, which is characterized by brown mottling or discoloration of the teeth. This occurs due to excessive fluoride affecting the enamel formation. ### Step 3: Analyze the Relationship Between Assertion and Reason Now, we need to determine if the reason correctly explains the assertion. - The assertion is about the addition of fluoride to maintain a concentration of 1 ppm for dental health benefits. - The reason explains the negative effects of fluoride at higher concentrations (above 2 ppm). **Conclusion**: While both statements are true, the reason does not directly explain the assertion. The assertion focuses on the benefits of fluoride at low concentrations, while the reason discusses the adverse effects at high concentrations. Therefore, the reason does not support the assertion. ### Final Answer: Both the assertion and reason are true, but the reason does not explain the assertion.
To analyze the assertion and reason provided in the question, we will break down the statements and evaluate their validity step by step. ### Step 1: Understand the Assertion The assertion states that soluble fluoride is often added to drinking water to bring its concentration up to 1 ppm (parts per million). **Evaluation**: This statement is true. Fluoride is added to drinking water in controlled amounts to help prevent dental cavities. A concentration of around 1 ppm is considered beneficial for dental health. ### Step 2: Understand the Reason ...
Promotional Banner

Topper's Solved these Questions

  • ENVIRONMENTAL CHEMISTRY

    NCERT FINGERTIPS ENGLISH|Exercise Environment Pollution|1 Videos

  • ENVIRONMENTAL CHEMISTRY

    NCERT FINGERTIPS ENGLISH|Exercise Atmospheric Pollution|17 Videos

  • ENVIRONMENTAL CHEMISTRY

    NCERT FINGERTIPS ENGLISH|Exercise EXAMPLAR PROBLEMS|12 Videos

  • CLASSIFICATION OF ELEMENTS AND PERIODICITY

    NCERT FINGERTIPS ENGLISH|Exercise Assertion And Reason|15 Videos

  • EQUILIBRIUM

    NCERT FINGERTIPS ENGLISH|Exercise Assertion And Reason|15 Videos

Similar Questions

Explore conceptually related problems

The presence of soluble fluoride ion upto 1 ppm concentration in drinking water , is :

14.2 g Na_2SO_4 is present in 10^2 kg water. Its concentration in ppm is

Statement-1: Deficiency of fluoride in drinking water is harmful to human being. and Statement-2: Fluoride concentration more than 10 ppm causes harmful effect to bones and teeth.

One litre sea water (d = 1.03g/ cm^3 ) contains 10.3 mg O_2 gas. Determine concentration of O_2 in ppm.

One litre sea water (d = 1.03g/ cm^3 ) contains 10.3 mg O_2 gas. Determine concentration of O_2 in ppm.

A 500 g toothpaste sample has 0.2 g fluoride concentration. What is the concentration of F^(Theta) in ppm ?

A 500 g toothpaste sample has 0.2 g fluoride concentration. What is the concentration of F^(Theta) in ppm ?

The product of the concentration of the ions of an electrolyte raised to power of their coefficients in the balanced chemical equation in the solution at any concentration . Its value is not constant and varies with change in concentration . Its value is not constant and varies with change in concentration . Its value is not constant and varies with change in concentration . Ionic product of the saturated solution is called solubility product K_(sp) (i) When K_(ip) = K_(sp) , the solution is just saturated and no precipitation takes place . (ii) When K_(ip) lt K_(sp) the solution is unsaturated and precipitation will not take place . (iii) When K_(ip) gt K_(sP) the solution is supersaturated and precipitation takes place . The solubility product K_(sp) , of sparingly soluable salt MX at 25^(@) is 2.5 xx10^(-9) . The solubility of the salt in mol L^(-1) at this temperature is :

Assertion: The concentration of pollutants in water or atmosphere is often expressed in terms of ppm Reason :Concentration in parts per million can be expressed as mass to mass, volume of volume and mass to volume .