Problem 1 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The presence of soluble fluoride ion upto 1 ppm concentration in drinking water, is : (a) harmful for teeth (b) harmful to skin (c) harmful to bones (d) safe for teeth

Step-by-Step Solution

Answer

The presence of 1 ppm fluoride in drinking water is safe for teeth.

Step 1: Understanding Parts Per Million (ppm)

Parts per million (ppm) is a unit of measurement for concentration. In this context, 1 ppm fluoride means 1 part of fluoride per million parts of water. It is important to understand this unit because it indicates the minute concentration levels being considered for fluoride ion presence in drinking water.

Step 2: Evaluating Fluoride's Effect on Teeth

Fluoride is often added to drinking water because it helps in preventing tooth decay. At low concentrations, such as 1 ppm, fluoride strengthens the enamel of teeth and is considered beneficial in preventing cavities.

Step 3: Considering Though Safety

While higher concentrations of fluoride can cause fluorosis (discoloration or damage to teeth), regulations establish that 1 ppm is a safe and effective level for protecting dental health. Thus, fluoride at 1 ppm concentration is deemed safe for teeth.

Key Concepts

Parts Per Million (ppm)

Parts per million, or ppm, is a way to describe extremely low concentrations of a substance in a solution. Picture one part of fluoride being mixed with one million parts of water; this creates a 1 ppm fluoride concentration. Understanding ppm is crucial because it highlights the trace levels at which different elements are present in drinking water. Knowing this helps us gauge safety and efficacy of minor components like fluoride in water supplies.

A concentration of 1 ppm is quite minuscule, illustrating how well water treatment plants control the amount of minerals or chemicals, like fluoride, in your drinking water. This small measurement unit is used globally to ensure safe drinking standards and is crucial in regulating substances that affect health.

Fluoride's Effect on Teeth

Fluoride is an element that plays a significant role in dental health. It is often added to drinking water due to its beneficial effects on teeth. The primary benefit of fluoride at low concentrations, such as 1 ppm, is its ability to prevent tooth decay.

Fluoride works by:

• Strengthening the enamel, which is the hard outer surface of teeth, making it more resistant to decay
• Helping to restore minerals to teeth surfaces that may have been eroded by acids from food and beverages
• Potentially disrupting the growth of harmful oral bacteria, thereby reducing the risk of cavities

In essence, even at a concentration as low as 1 ppm, fluoride acts as a defender against dental problems, making it a valuable component of community water systems for ensuring dental health.

Fluorosis

While fluoride can be extremely beneficial at low concentrations, it is essential to be aware of the potential condition known as fluorosis. Fluorosis occurs when too much fluoride is ingested over a long period during tooth development.

It can manifest as:

• Mild forms, which might only result in tiny, white specks on the enamel
• Severe forms, which could cause brown or black staining and even pitting of the enamel

Fluorosis is generally not harmful beyond these cosmetic effects, but it does highlight the importance of regulating fluoride levels to stay within safe limits. Standards are established (such as the 1 ppm level for drinking water) to prevent such conditions, ensuring that the fluoride in water has beneficial effects without leading to unnecessary risks.