Question 6 of 14intermediate🔧 ApplyShort Answer3 marks

Is curdling of milk a physical or chemical change? Justify your statement.

Correct Answer

Curdling of milk is a chemical change.

When milk curdles, it transforms into curd (yogurt), which is a different substance with different properties such as taste, texture, and smell. The process involves the action of bacteria or acidic substances that cause proteins in the milk to coagulate, forming a new substance.

Once milk has turned into curd, it cannot be converted back to milk, indicating that the change is irreversible.

The formation of a new substance (curd) with different properties confirms that curdling is a chemical change.

Exercise: Let Us Enhance Our Learning | Q: 6 | (Page Page 14)
For More Understanding

Explanation

The chapter mentions that the changing of milk into curd is a useful/desirable change in daily life. A chemical change is defined as one in which one or more new substances are formed. Since curd is a different substance from milk with different properties, and the change cannot be reversed, curdling is classified as a chemical change.

Solution Steps

  1. Curdling of milk is identified as a chemical change.

  2. Milk transforms into curd (yogurt), which has different properties such as taste, texture, and smell.

  3. The process involves bacteria or acidic substances causing proteins to coagulate.

  4. The change is irreversible – curd cannot be converted back to milk.

  5. Formation of a new substance with different properties confirms it is a chemical change.

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