Question

In spite of various acid and base-producing reactions in our body, the pH of our blood is (a) \(5.4\) (b) \(6.4\) (c) \(7.4\) (d) \(8.4\)

Short answer

The correct option is (c) 7.4.

Step-by-step solution

Understanding pH scale

The pH scale measures how acidic or basic a substance is. It ranges from 0-14. A pH of 7 is neutral. A pH less than 7 is acidic and a pH greater than 7 is basic.

Identifying human blood pH

In the human body, the pH of blood has to be maintained in a very narrow range to function normally and is tightly regulated between 7.35 and 7.45, slightly basic.

Choose correct option

From the options given (5.4, 6.4, 7.4, 8.4), the closest to this range is 7.4.

Key concepts

pH scale

The pH scale is an important scientific tool that measures how acidic or basic a solution is. It ranges from 0 to 14, allowing us to easily understand the acidity or basicity of any given substance. At the midpoint, we have the number 7, which stands for neutral. Neutral substances are neither acidic nor basic.

Here’s how the scale is divided:

• Solutions with a pH less than 7 are considered acidic.
• Solutions with a pH greater than 7 are basic (or alkaline).

Acids and bases are abundant in nature and many are found in household items, such as vinegar, which is acidic, and baking soda, which is basic.
Understanding the pH scale helps in various fields, from chemistry to biology, as it gives an insight into the nature of substances by measuring the concentration of hydrogen ions.

acidic and basic reactions

Acidic and basic reactions are fundamental to both chemistry and biology. They play a crucial role in many natural and industrial processes. In an acidic reaction, a proton donor (acid) transfers protons to another substance, known as a base.
In contrast, basic reactions typically involve bases accepting protons or donating electron pairs.

Here's a quick guide to identify these reactions:

• Acids taste sour and can corrode metals. Lemon juice and vinegar are examples of substances that produce acidic reactions.
• Bases taste bitter and feel slippery. Soap and baking soda are common bases.

In the human body, these reactions are essential for various metabolic processes. The balance between these reactions is vital to maintain homeostasis. For example, in our stomach, hydrochloric acid helps digest food, showcasing an acidic environment.

human body pH regulation

Maintaining the correct pH balance in the human body is crucial for overall health. Blood, for instance, is maintained in a narrow pH range of approximately 7.35 to 7.45. This slightly basic range is optimal for our biological functions.

Several mechanisms help regulate the body's pH:

• The kidneys and lungs play a key role in balancing the pH by removing excess acids or bases.
• Buffers present in the body resist significant changes in pH by neutralizing acids and bases.

Despite the body constantly undergoing reactions that produce acidic and basic by-products, these systems ensure blood pH remains stable. This careful regulation is essential, as a deviation from the normal range can disrupt bodily functions, affecting processes such as oxygen transport and enzyme activity.