All questions of Neutralisation for Grade 6 Exam

Some of the natural indicators are red cabbage juice, onion paste, turmeric, lemon juice etc. Natural indicators are turmric,litmus,china rose etc are some natural indicators. Some Natural Indicators are red Cabbage juice,turmeric,china rose[hibiscus] and litmus.

China Rose Indicator Test with Lemon Juice
To determine the final color of lemon juice when tested with China rose indicator, we need to understand the reaction between the two substances.

Reaction with China Rose Indicator:
- China rose indicator is a natural pH indicator that changes color in response to the acidity or alkalinity of a solution.
- Lemon juice is acidic in nature due to the presence of citric acid.

Final Color:
When lemon juice is tested with China rose indicator, the initial color of the indicator may be pink or red depending on its concentration. However, when it comes in contact with the acidic lemon juice, the color changes to a dark pink or magenta.
Therefore, the final color of lemon juice when tested with China rose indicator is dark pink (magenta). This color change indicates the acidic nature of lemon juice.

Quick Lime (Calcium Oxide) for Treating Acidic Soil
Quick lime, also known as calcium oxide, is commonly used to treat excessively acidic soil. Here's why:
- Neutralization of Soil pH: Quick lime helps raise the pH level of acidic soil by neutralizing the acidity. This is important because most plants thrive in slightly acidic to neutral soil conditions.
- Calcium Nutrient Source: Quick lime also provides calcium to the soil, which is an essential nutrient for plant growth. Calcium helps in root development, cell wall formation, and overall plant health.
- Improves Soil Structure: Quick lime can help improve soil structure by reducing soil compaction and increasing water infiltration. This allows for better root growth and nutrient uptake by plants.
- Enhances Nutrient Availability: By adjusting the pH level of the soil, quick lime helps make nutrients more available to plants. This can lead to healthier and more productive plant growth.
In conclusion, quick lime is a valuable substance for treating excessively acidic soil due to its ability to neutralize acidity, provide essential nutrients, improve soil structure, and enhance nutrient availability for plants.

Formation of Acid Rain
Acid rain is formed when carbon dioxide dissolves in raindrops. Here's how it happens:

Dissolution of Carbon Dioxide
- Carbon dioxide, a gas present in the atmosphere, dissolves in rainwater to form carbonic acid.
- The chemical reaction can be represented as:
CO2 (gas) + H2O (liquid) → H2CO3 (carbonic acid)

Release of Sulfur Dioxide and Nitrogen Oxides
- In addition to carbon dioxide, sulfur dioxide (SO2) and nitrogen oxides (NOx) emitted from burning fossil fuels can also combine with rainwater to form sulfuric acid and nitric acid, respectively.
- These acids contribute to the acidity of rainwater, leading to acid rain.
- The chemical reactions involving sulfur dioxide and nitrogen oxides are:
SO2 + H2O → H2SO3 (sulfurous acid)
2NO2 + H2O → HNO3 + HNO2 (nitric acid + nitrous acid)

Environmental Impact
- Acid rain can have detrimental effects on the environment, including the acidification of soil and water bodies, damage to vegetation, and corrosion of buildings and infrastructure.
- It can also impact aquatic life by altering the pH of water bodies and harming aquatic organisms.
In conclusion, acid rain is primarily formed when carbon dioxide, sulfur dioxide, and nitrogen oxides react with rainwater to produce acidic compounds. Understanding the formation of acid rain is crucial for addressing its environmental consequences and mitigating its harmful effects.

Understanding China Rose Indicator
The statement is indeed **True**. Let's explore why.

What is China Rose Indicator?
- The China rose indicator, also known as hibiscus extract, is a natural pH indicator derived from the petals of the hibiscus flower.
- It contains anthocyanins, which change color based on the acidity or basicity of the solution.

Color Changes in Solutions
- **Acidic Solutions:**
- When added to acidic solutions (like lemon juice or vinegar), the China rose indicator turns **dark pink (magenta)**.
- This color change occurs because the anthocyanins react with hydrogen ions (H⁺) present in acidic environments.
- **Basic Solutions:**
- In contrast, when the indicator is introduced to alkaline or basic solutions (such as baking soda solution), it shifts to a **green** hue.
- This color change indicates a decrease in the concentration of hydrogen ions, resulting in a more neutral or basic environment.

Practical Applications
- The China rose indicator can be used in classrooms and laboratories to visually demonstrate the pH levels of various solutions.
- It serves as an accessible and visually engaging tool to educate students about acids, bases, and the concept of pH.

Conclusion
In summary, the China rose indicator effectively demonstrates acid-base chemistry through its color changes, confirming that the statement is **True**.

When we add phenolphthalein indicator to a base, and a base only, it turns dark pink. It does not change color in an acid or a neutral substance. If no change is observed, it is either an acid or a neutral substance. So, option c.

Actually tomato contains oxalic acid.
tamarind contains tartaric acid
phosphoric is used for fertilizers, detergents and soft drinks
lactic acid is produced when you do exercises i.e the muscle cells and red blood cells produces lactic acid
so we can conclude that oxalic acid is present in tomato

Formation of Sodium Chloride in Neutralization Reaction:
When hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) in a neutralization reaction, a new substance called sodium chloride (NaCl) is formed.

Explanation:
- Hydrochloric acid (HCl) is a strong acid, and sodium hydroxide (NaOH) is a strong base.
- In the neutralization reaction between HCl and NaOH, hydrogen ions (H+) from the acid combine with hydroxide ions (OH-) from the base to form water (H2O).
- The remaining ions, chloride ions (Cl-) from the acid and sodium ions (Na+) from the base, combine to form sodium chloride (NaCl), which is a salt.
- The chemical equation for the neutralization reaction is:
HCl + NaOH → NaCl + H2O

Significance of Sodium Chloride:
- Sodium chloride, commonly known as table salt, is a vital compound used in various industries, food preparation, and for seasoning food.
- It is also essential for maintaining the electrolyte balance in the body and plays a crucial role in nerve function and muscle contraction.

Conclusion:
- In the neutralization reaction between hydrochloric acid and sodium hydroxide, sodium chloride is formed as a new substance. This reaction is commonly used in laboratories and industries to produce salts and water.

Explanation:
•Putting a drop of soap solution on turmeric paper will make the paper turn into red color.
•That is because due to the process of indication.
•Turmeric turns red when reacted with base and green when reacted with acid.
•Soap solution is a base
Conclusion:
Turmeric paper when reacted with soap solution(base) turns the color of the paper red.

Introduction:
Acidic soil is characterized by a low pH level, typically below 7. This type of soil can be problematic for plant growth as it affects nutrient availability and can lead to nutrient deficiencies. To improve the pH level of acidic soil, a base is commonly used to neutralize the acidity and make it more suitable for plant growth.

Base commonly used to treat acidic soil:
The correct base commonly used to treat acidic soil is Calcium Hydroxide (option D).

Explanation:
Calcium hydroxide, also known as agricultural lime or garden lime, is a common base used to treat acidic soil. It is an alkaline substance and has the ability to neutralize the acidity in the soil by increasing the pH level.

How does Calcium Hydroxide work?
When calcium hydroxide is applied to acidic soil, it reacts with the hydrogen ions (H+) present in the soil solution. This reaction results in the formation of water and calcium ions (Ca2+). The calcium ions then combine with carbonate ions (CO32-) naturally present in the soil to form calcium carbonate (CaCO3). Calcium carbonate is a neutral compound that helps to raise the soil pH and reduce its acidity.

Benefits of using Calcium Hydroxide:
Using calcium hydroxide to treat acidic soil offers several benefits:

1. Neutralizes soil acidity: The primary benefit of using calcium hydroxide is its ability to neutralize soil acidity by raising the pH level. This creates a more favorable environment for plant growth.

2. Increases nutrient availability: Acidic soil tends to lock up essential nutrients, making them less available to plants. By raising the pH level, calcium hydroxide helps to release these nutrients, making them more accessible for plant uptake.

3. Improves soil structure: Acidic soil is often compacted and poorly structured. The application of calcium hydroxide can help improve soil structure by promoting better aggregation and allowing for better water infiltration and root penetration.

4. Enhances microbial activity: Many beneficial soil microorganisms prefer a neutral pH environment. By neutralizing soil acidity, calcium hydroxide can promote the growth and activity of these beneficial microorganisms, improving overall soil health.

Conclusion:
In conclusion, calcium hydroxide (option D) is commonly used as a base to treat acidic soil. Its ability to neutralize acidity, increase nutrient availability, improve soil structure, and enhance microbial activity makes it an effective choice for improving the pH level of acidic soil and creating a more suitable environment for plant growth.

In a neutralization reaction, an acid reacts with a base to form salt and water. This process is characterized by the combination of H⁺ ions from the acid and OH⁻ ions from the base to form water (H₂O), and the remaining ions form a salt.

Organic matter, such as compost, releases acids when decomposed. These acids help to neutralize the basic nature of the soil, making it more suitable for plant growth.

Litmus Paper in Acidic Solution
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The color change of litmus paper when added to an acidic solution is a key indicator of the solution's pH level. Litmus paper is a pH indicator that changes color in response to the acidity or alkalinity of a solution.

Color Change to Red
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When litmus paper is added to an acidic solution, it turns red. This is because acidic solutions have a pH below 7, indicating a higher concentration of hydrogen ions. The red color change of litmus paper in an acidic solution is a result of the chemical reaction between the hydrogen ions in the acid and the dye on the litmus paper.

Explanation
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Litmus paper contains a dye that changes color in response to the concentration of hydrogen ions in a solution. In an acidic solution, there is an excess of hydrogen ions, which react with the dye on the litmus paper, causing it to turn red. This color change indicates the acidic nature of the solution.

Conclusion
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In conclusion, when litmus paper is added to an acidic solution, it turns red due to the presence of hydrogen ions. This color change is a useful indicator of the acidity of the solution and can help determine its pH level.

Importance of Neutralizing Factory Wastes Before Disposal into Water Bodies

Preventing the Killing of Aquatic Organisms
- When factory wastes contain acids or other harmful chemicals, they can have devastating effects on aquatic life.
- The acidic nature of the waste can disrupt the pH balance of the water, making it unsuitable for many aquatic organisms.
- Aquatic organisms may suffer from burns, organ damage, or even death when exposed to acidic waste.

Protecting the Ecosystem
- Aquatic organisms play a crucial role in the ecosystem by maintaining the balance of the food chain.
- If these organisms are killed off due to the acidic factory waste, it can lead to a ripple effect throughout the ecosystem.
- Other species that depend on these organisms for food or habitat may also be affected, causing a domino effect of negative consequences.

Promoting Water Quality
- Neutralizing factory wastes before disposal helps to maintain the quality of water bodies.
- Clean water is essential for human consumption, agriculture, and the overall health of the environment.
- By preventing the introduction of harmful chemicals into water bodies, we can ensure that the water remains safe and usable for various purposes.
In conclusion, neutralizing factory wastes before disposal into water bodies is crucial to prevent the killing of aquatic organisms and protect the ecosystem. It also helps to promote water quality and ensure the sustainability of our natural resources.

Phenolphthalein is a commonly used synthetic indicator to test the acidic or basic nature of a substance. Here is an explanation of why phenolphthalein is used as an indicator and how it works:

Indicators:
Indicators are substances that change their color in the presence of acids or bases. They are used to detect the presence and determine the nature of these substances in a solution. Indicators exist in both natural and synthetic forms. Synthetic indicators are often preferred due to their stability and reliability.

Phenolphthalein:
Phenolphthalein is a synthetic indicator that is frequently used in acid-base titrations and to test the pH of a substance. It is a colorless compound in its acidic form and turns pink or purple in the presence of a base. Phenolphthalein can be used to detect both strong and weak bases.

Working of Phenolphthalein:
When phenolphthalein is added to a solution, it undergoes a chemical reaction with the base present in the solution. In an acidic solution, the concentration of H+ ions is high, and these ions react with phenolphthalein to keep it colorless. However, in a basic solution, the concentration of OH- ions is high, and they react with phenolphthalein to produce an ion that is pink or purple in color.

Color Change:
The color change of phenolphthalein from colorless to pink or purple occurs at a specific pH range, known as the indicator's transition range. For phenolphthalein, the transition range is typically between pH 8.2 and 10.0. This means that phenolphthalein will remain colorless in acidic solutions with a pH below 8.2, but as the pH increases and becomes more basic, the indicator will gradually turn pink or purple.

Conclusion:
Phenolphthalein is a commonly used synthetic indicator to test the acidic or basic nature of a substance. Its colorless to pink/purple color change in the presence of a base makes it a reliable indicator for determining the pH of a solution.

Role of Bases in Treating Factory Wastes

Neutralization of Acid
Bases play a crucial role in treating factory wastes by neutralizing the acid present in the waste. Many industrial processes produce acidic waste products, which can be harmful to the environment if not properly treated. When bases are added to acidic wastes, a neutralization reaction occurs, resulting in the formation of water and a salt. This process helps to reduce the acidity of the waste, making it less harmful to the environment.

Prevention of Environmental Damage
By neutralizing the acid in factory wastes, bases help to prevent environmental damage. Acidic wastes can contaminate soil, water, and air, leading to harmful effects on plants, animals, and humans. Neutralizing the acid in these wastes helps to reduce their harmful impact on the environment, protecting ecosystems and human health.

Facilitation of Waste Treatment
Bases also play a role in facilitating the treatment of factory wastes. By neutralizing the acid, bases help to stabilize the waste, making it easier to handle and dispose of properly. This process enables the effective treatment and management of industrial wastes, ensuring that they do not pose a threat to the environment or public health.
In conclusion, bases play a critical role in treating factory wastes by neutralizing the acid present in the waste. This process helps to prevent environmental damage, facilitate waste treatment, and protect ecosystems and human health from the harmful effects of acidic industrial wastes.

Distilled Water pH Nature
Distilled water is considered neutral in terms of pH.

Explanation
- Distilled water has a pH of around 7, which is considered neutral on the pH scale.
- The pH scale ranges from 0 to 14, with 7 being neutral, lower values indicating acidity, and higher values indicating alkalinity.
- Distilled water is created through the process of distillation, which involves heating water to create steam, then cooling and condensing the steam back into liquid form. This process removes impurities and most dissolved substances from the water, resulting in a pure form of H2O.
- Since distilled water is free from any additional ions or impurities that could influence its pH, it typically has a pH of 7, making it neutral.
Therefore, the pH nature of distilled water is neutral.

Identifying substances using turmeric indicator:
Identifying substances using turmeric indicator involves observing the color changes that occur when turmeric is exposed to different solutions. Turmeric indicator is commonly used in chemistry to detect the presence of acids and bases based on color changes.

Explanation of option 'B':

Sugar solution: Sugar solution does not change the color of turmeric indicator. Therefore, when turmeric indicator is added to a sugar solution, it will not show any significant color change.

Hydrochloric acid: Hydrochloric acid turns turmeric indicator yellow. This is because hydrochloric acid is an acid and acids turn turmeric indicator yellow.

Sodium hydroxide: Sodium hydroxide turns turmeric indicator red. This is because sodium hydroxide is a base and bases turn turmeric indicator red.
Therefore, based on the color changes observed with turmeric indicator, we can conclude that option 'B' is the correct identification of the substances.

Chemical Name of Common Salt Formed during Neutralization of Sodium Hydroxide and Hydrochloric Acid:

When sodium hydroxide (NaOH) and hydrochloric acid (HCl) react together in a neutralization reaction, a chemical compound called sodium chloride (NaCl) is formed. Sodium chloride is commonly known as table salt.

Neutralization Reaction:
The reaction between sodium hydroxide and hydrochloric acid can be represented by the following balanced chemical equation:

NaOH + HCl → NaCl + H2O

In this reaction, one molecule of sodium hydroxide reacts with one molecule of hydrochloric acid to produce one molecule of sodium chloride and one molecule of water.

Explanation:

- Sodium hydroxide (NaOH) is a strong base, and hydrochloric acid (HCl) is a strong acid. When these two substances react together, they undergo a neutralization reaction.
- In a neutralization reaction, an acid reacts with a base to form a salt and water. The acidity of the acid is neutralized by the basicity of the base, resulting in the formation of a neutral product.
- In the case of the reaction between sodium hydroxide and hydrochloric acid, the sodium ion (Na+) from sodium hydroxide combines with the chloride ion (Cl-) from hydrochloric acid to form sodium chloride (NaCl).
- The other product of the reaction is water (H2O), which is formed by the combination of the hydrogen ion (H+) from hydrochloric acid and the hydroxide ion (OH-) from sodium hydroxide.
- Sodium chloride is a white crystalline solid that is highly soluble in water. It is widely used as a seasoning and preservative in food, as well as in various industrial processes.
- The chemical formula for sodium chloride is NaCl, where Na represents sodium and Cl represents chlorine.

Conclusion:

The chemical name of the common salt formed during the neutralization of sodium hydroxide and hydrochloric acid is sodium chloride (NaCl). This reaction is a typical example of a neutralization reaction, where a salt and water are produced by the combination of an acid and a base. Sodium chloride, or table salt, is widely used in various applications due to its numerous properties and uses.

Antacids like milk of magnesia contain basic substances that neutralize the excessive acid in the stomach, providing relief from the discomfort and pain associated with indigestion.

Milk of Magnesia provides relief from indigestion by acting as a base.

Indigestion, also known as dyspepsia, is a common condition characterized by discomfort or pain in the upper abdomen. It is often caused by excessive stomach acid or an imbalance in the digestive system. Milk of Magnesia, a popular over-the-counter medication, is commonly used to relieve indigestion symptoms. It contains magnesium hydroxide, which acts as an antacid and helps neutralize excess stomach acid.

How Milk of Magnesia works:

1. Alkaline properties: Milk of Magnesia is an alkaline substance, meaning it has a high pH level. When consumed, it reacts with the stomach acid, which has a low pH level, and helps neutralize it. This neutralization process reduces the overall acidity in the stomach, providing relief from indigestion symptoms.

2. Buffering effect: The active ingredient in Milk of Magnesia, magnesium hydroxide, acts as a buffering agent. It absorbs excess acid and converts it into magnesium chloride and water. This process helps maintain the pH balance in the stomach and prevents acid-related discomfort.

3. Coating effect: Milk of Magnesia also has a soothing effect on the lining of the stomach and esophagus. It forms a protective coating that helps alleviate irritation and inflammation caused by stomach acid. This coating effect can provide relief from symptoms like heartburn and sour stomach.

4. Regulation of bowel movements: In addition to its antacid properties, Milk of Magnesia is also known for its mild laxative effect. It helps relieve constipation by drawing water into the colon, softening the stool, and promoting bowel movements. This can be beneficial for individuals experiencing indigestion symptoms related to constipation.

5. Overall relief: By acting as a base, neutralizing stomach acid, and providing a protective coating, Milk of Magnesia helps alleviate the discomfort associated with indigestion. It provides relief from symptoms such as heartburn, bloating, nausea, and abdominal pain.

In conclusion, Milk of Magnesia acts as a base and helps neutralize excess stomach acid. It also provides a protective coating and regulates bowel movements, providing relief from indigestion symptoms. However, it is always advisable to consult a healthcare professional before using any medication for indigestion or other digestive issues.

The result of the neutralization reaction between hydrochloric acid and sodium hydroxide is water. This reaction is a typical example of an acid-base reaction, where an acid and a base react to form a salt and water.

Neutralization Reaction:
In a neutralization reaction, the hydrogen ions (H+) from the acid combine with the hydroxide ions (OH-) from the base to form water (H2O). The remaining ions from the acid and base combine to form a salt. In this case, the salt formed is sodium chloride (NaCl).

Chemical Equation:
The chemical equation for the neutralization reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is:

HCl + NaOH → NaCl + H2O

The hydrochloric acid donates a hydrogen ion (H+) to the sodium hydroxide, resulting in the formation of water and sodium chloride.

Explanation:
During the reaction, the hydrochloric acid dissociates into hydrogen ions (H+) and chloride ions (Cl-). Similarly, sodium hydroxide dissociates into sodium ions (Na+) and hydroxide ions (OH-).

The hydrogen ions from the hydrochloric acid combine with the hydroxide ions from the sodium hydroxide to form water molecules. This is an exothermic reaction, releasing energy in the form of heat.

The remaining ions, sodium (Na+) and chloride (Cl-), combine to form sodium chloride (NaCl), which is a salt. The salt remains dissolved in the water, forming a homogeneous solution.

Conclusion:
In conclusion, the neutralization reaction between hydrochloric acid and sodium hydroxide results in the formation of water and sodium chloride. This reaction is commonly used in various applications, such as in the laboratory to prepare solutions of specific pH or in everyday life for acid-base neutralization.