How can you separate alumina from silica | Class 12 Chemistry Chapter General Principles and Processes of Isolation of Elements, General Principles and Processes of Isolation of Elements NCERT Solutions

Previous / historical NCERT chapter

This chapter belongs to a previous NCERT/CBSE curriculum and is not part of the current 2026-27 chapter list. Removed in 2022-23.

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter General Principles and Processes of Isolation of Elements. This page offers a step-by-step solution to the specific question from Exercise 2, Question 22:

How can you separate alumina from silica in bauxite ore associated with silica? Give equations, if any.

. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 22:

How can you separate alumina from silica in bauxite ore associated with silica? Give equations, if any.

Answer:

To separate alumina from silica in bauxite ore associated with silica, first the powdered ore is digested with a concentrated NaOH solution at 473 - 523 K and 35 - 36 bar pressure. This results in the leaching out of alumina (Al2O3) as sodium aluminate and silica (SiO2) as sodium silicate leaving the impurities behind.

Then, CO2 gas is passed through the resulting solution to neutralize the aluminate in the solution, which results in the precipitation of hydrated alumina. To induce precipitation, the solution is seeded with freshly prepared samples of hydrated alumina.

During this process, sodium silicate remains in the solution. The obtained hydrated alumina is filtered, dried, and heated to get back pure alumina.


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about General Principles and Processes of Isolation of Elements.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Latest Blog Posts

Stay updated with our latest educational content and study tips

How to Return to Work After a Career Break: Skills, Jobs and Preparation in 2026

It’s not about starting over if you took a break to care for children, take care of yourself, be healthy or for any other reason. This is a realistic strategy for the recovery of skills, selection of the right job, and overcoming the resume problem. One year, three years or 10 years of a career … Read more

Read More

Best Career Options After Class 12 for Average Students in 2026

There’s no need to score 95% or achieve a JEE/NEET rank. You don’t need to score 95% or rank in JEE/NEET to build a solid career. A candid and pragmatic guide to the routes that actually work for students who have an average mark and what to do when faced with the options. ​ If … Read more

Read More

Coaching vs Self-Study: Which is Best in 2026 for Competitive Exams?

AI tools, online platforms that are much cheaper than coaching centres and the changing idea of what “structure” even means have upended this argument more in the past two years than in the decade preceding it. Here’s what is really the case for 2026 – and what has actually stayed the same. If you look … Read more

Read More

Career Change After 30: How to Transition from Non-Tech to IT or Data Science

Starting to make a new career after 30 isn’t a start from scratch. Marketing, teaching, financial, retail, healthcare, sales and other professionals can pursue careers in technology by applying the existing knowledge and skills they have acquired to new technology skills. There are various ways to enter the technology industry, such as in IT support, … Read more

Read More

Related Student Tools

Comments

  • Naseema
  • Nov 01, 2019

So thankful


  • Naseema
  • Nov 01, 2019

In second reaction the carbons and hydrogens are not balanced


  • aayush
  • Feb 27, 2019

really helpful


  • piyush
  • Feb 15, 2018

you are great


Add Comment

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 22: How can you separate alumina from silica in bauxite ore associated with silica? Give equations, if a....

Ask a Question
Keep learning

Discover More on SaralStudy

Explore all articles