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The following steps are involved in a dairy plant to prepare clarified butter/Ghee. A. Milk is pasteurised B. Then milk is set into curd C. Curd is churned in centrifuge to separate butter D. Butter is heated to get clarified butter (Ghee) E. Filtered and packed Which of the following above steps are physical changes and chemical changes?

The following steps are involved in a dairy plant to prepare clarified butter/Ghee. A. Milk is pasteurised B. Then milk is set into curd C. Curd is churned in centrifuge to separate butter D. Butter is heated to get clarified butter (Ghee) E. Filtered and packed Which of the following above steps are physical changes and chemical changes? Correct Answer Physical changes - A, C, E ; chemical changes - B, D

The correct answer is -

Physical changes - A, C, E ;

Chemical changes - B, D.

Concept:

  • Physical Change:
    • It is a type of change in the matter without changing the chemical composition of matter. 
    • It is usually reversible.
    • In the physical change, no new products are formed.
  • Chemical Change:
    • It is a change in the chemical composition of matter. 
    • It is usually irreversible. 
    • In the chemical change, new products are formed.

Explanation:
Milk is pasteurized - Physical change

  • Milk is quickly heated to a high temperature and then quickly cooled during the pasteurization process.
  • This high temperature ensures that all bacteria in the milk are killed, and the cooling ensures that the milk does not evaporate completely. This is a physical change because the process is reversible.

Then the milk is set into curd - Chemical change

  • The transformation of milk into curd is a chemical change that results in the formation of a new substance (lactic acid).
  • The curd is formed as a result of a chemical reaction between lactic acid bacteria and casein.
  • The resulting curd tastes different from the original substance. Furthermore, once the curd has formed, milk cannot be obtained from it. It is an irreversible change.

Curd is churned in a centrifuge to separate butter - Physical change

  • The process of shaking up milk to make butter is known as churning. Centrifugation is the scientific term for this process. This process is a physical process.
  • The butter in milk is actually the fat portion. During the centrifugation process, the heavy fat particles are centrifuged at a place known as the butter churn or butter.

Butter is heated to get clarified butter (Ghee) - Chemical change

  • When the butter is heated, the emulsion separates and the fat separates from the water, forming two layers. This separated fat layer is commonly referred to as ghee. Ghee and butter have different properties, and we cannot extract butter from ghee. As a result, it is a chemical change.

Filtered and packed - Physical change

  • Ghee is filtered and packed after it has been formed.
  • Filtration is a physical separation process that uses a filter medium with a complex structure through which only fluid can pass to separate solid matter and fluid from a mixture.
  • As a result, the filtering and packing of ghee is a reversible process, resulting in a physical change.

Related Questions

In a mixture of ghee and dalda, the ratio of ghee to dalda is 5 : a. When 5 litres of ghee were added in the mixture then, the concentration of dalda becomes 50% but when 2 litres of dalda were added in the mixture then the concentration of ghee becomes 40%.  Quantity I : ghee will be what part of the mixture when, 10 litres of ghee were added in the original mixture? Quantity II : Dalda will be what part of the mixture when 3 litres of dalda were added in the original mixture?
In the following question below some statements are given followed by some conclusions. Taking the given statements to be true even if they seem to be at variance from commonly known facts, read all the conclusions and then decide which of the given conclusions logically follows the given statements. Statements: A few bread is butter. Some curd are butter. No curd is cheese. Conclusions: I. Some butter are not cheese. II. Some bread are curd. III. Some bread are cheese. IV. All butter are curd. 
Two statements are followed by three Conclusions I, II and III. You have to consider the statements to be true, even if they seem to be at variance from commonly known facts. You are to decide which of the given conclusions can definitely be drawn from the given statements and indicate your answer accordingly. Statements: I. Milk supply in Maharashtra was badly hit after thousands of dairy farmers launched a protest on Monday, demanding better price and subsidy of Rs 5 per litre. Tankers supplying milk to major cities including Mumbai, Pune, Nagpur, Nashik and others were blocked early morning leading to sudden crisis.  II. The agriculture ministry had mooted a proposal asking railways to make milk available at railway stations and at the meeting, sources said representatives from Amul India suggested that the national transporter could provide stalls to dairy companies or cooperatives where they could sell their products.  Conclusions: I. Representatives of Amul India and food safety body FSSAI are willing to discuss issues and concerns of the dairy sector in the backdrop of the farmers agitation in Maharashtra that had led to severe shortage of milk in the state.  II. The farmers' groups and Maharashtra Kisan Sabha, are demanding a GST waiver on butter and milk powder apart from the subsidy. III. Railways is drawing up a plan to make milk available at railway stations across the country to promote its consumption.
In some quantity of ghee, 60% is pure ghee and 40% is vanaspati. If 10 kg of pure ghee is added, then the strength of vanaspati ghee becomes 20%. The original quantity was :
In some quantity of ghee, 60% is pure ghee and 40% is vanaspati. If 10 kg pure ghee is added, then the strength of vanaspati ghee becomes 20%. The original quantity was :
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