All Exams Test series for 1 year @ ₹349 only
Question

The maximum amount of substitution of Al for Si is found in :

This question was previously asked in
CUET PG 2026 Agri-Business Management Question Paper (25-Mar-2026) (Shift 2)
The correct answer is
Anorthite

The question involves identifying which mineral allows the maximum substitution of aluminum (Al) for silicon (Si) in its crystal structure. This kind of substitution is common in the feldspar mineral group due to the similar ionic radii and charges of Al3+ and Si4+. Understanding the chemical composition of each option can help in determining where this substitution is most prevalent.

  • Albite (NaAlSi3O8): Albite is a sodium-rich feldspar with minimal substitution of Al for Si. The chemical formula shows that it contains only one aluminum atom per molecule.
  • Anorthite (CaAl2Si2O8): Anorthite is a calcium-rich feldspar with a high level of Al substitution. Its formula indicates two aluminum atoms, which allows for more Al substitution for Si.
  • Oligoclase (Na0.9Ca0.1Al1.1Si2.9O8): Oligoclase is part of the plagioclase series and contains moderate aluminum substitution, more than Albite but less than Anorthite.
  • Andesine (Na0.7Ca0.3Al1.3Si2.7O8): Andesine also belongs to the plagioclase series with an intermediate Al substitution level between oligoclase and anorthite.

The key to solving this question is understanding the plagioclase feldspar series, which ranges from sodium-rich albite to calcium-rich anorthite. In this series, the substitution of Al for Si increases from albite to anorthite. Therefore, the correct answer is Anorthite, as it allows for the maximum Al substitution due to its chemical composition of CaAl2Si2O8.

In summary, Anorthite allows the maximum substitution of aluminum for silicon because it has a higher aluminum-to-silicon ratio compared to the other minerals listed, which makes it the correct answer.

Was this answer helpful?

Similar Questions

  1. Match List - I with List - II.

    List - I
    Optical feature
    List - II
    Optical diagram
    A. Wave front (isotropic)I. Ellipse
    B. Wave surface (isotropic)II. Sphere
    C. Wave front (anisotropic)III. ellipsoidal
    D. Wave surface (anisotropic)IV. circle

    Choose the correct answer from the options given below :

  2. Match List - I with List - II.

    List - I
    Earth's Internal Segment
    List - II
    Approximate Average Thickness
    A. LithosphereI. 2 km
    B. MohoII. 105 km
    C. CoreIII. 2900 km
    D. MantleIV. 3500 km

    Choose the correct answer from the options given below :

  3. Match List - I with List - II.

    List - I
    Fold type
    List - II
    Characteristics
    A. Polyclinal foldsI. Folds developed in many steps
    B. Fan foldsII. Folds with variable axial surfaces
    C. Conjugate foldsIII. Folds in which axial surfaces dip towards each other
    D. Cross foldsIV. Folds in which both the limbs are overturned

    Choose the correct answer from the options given below :

  4. Match List - I with List - II.

    List - I
    Joint type
    List - II
    Stress type
    A. Sheet jointsI. Contractional
    B. Extension jointsII. Residual
    C. Columnar jointsIII. Compressional
    D. Conjugate jointsIV. Tensional

    Choose the correct answer from the options given below :

  5. Match List - I with List - II.

    List - I
    Texture
    List - II
    Rock
    A. OphiticI. Syenite
    B. TrachytoidII. Dolerite
    C. MyrmekiteIII. Basalt
    D. GlomeroporphyriticIV. Granite

    Choose the correct answer from the options given below :

  6. Match List - I with List - II.

    List - I
    Deposit
    List - II
    Origin
    A. DeluviumI. Deposits formed by mass wasting
    B. EluviumII. Residual products of the breakdown of primary rocks
    C. ProluviumIII. Residual products of the breakdown of mobile rocks
    D. ColluviumIV. Sediments deposited by mudflows and other flash flows

    Choose the correct answer from the options given below :

  7. Match List - I with List - II.

    List - I
    Minaral Resource
    List - II
    Place
    A. CopperI. Ambadongar
    B. Lead and zincII. Bastar
    C. IronIII. Zawar
    D. FluoriteIV. Khetri

    Choose the correct answer from the options given below :

  8. Match List - I with List - II.

    List - I
    Mineral Resouce
    List - II
    Stratigraphic Unit
    A. Copper and ironI. Damuda
    B. PetroleumII. Singhbhum
    C. CoalIII. Eastern Ghat Khondalite
    D. BauxiteIV. Barail

    Choose the correct answer from the options given below :

  9. On which of the following bases the Dharwar succession of Karnataka is divided into Lower and Upper Dharwar ?

    A. Unconformity
    B. Fossil evidence
    C. Geochronological data
    D. Economic minerals

    Choose the correct answer from the options given below :

  10. Schistosity forms due to :

    A. Dynamothermal metamorphism
    B. Contact metamorphism
    C. Plutonic metamorphism
    D. Thermal metamorphism

    Choose the correct answer from the options given below :


Important Questions from Mixed Topic (CUET PG)

  1. Who was the founder of Bolshevik Communist party?
  2. What is the key guide to statecraft in the realist tradition?
  3. Chronologically arrange the events in the Cold War period.
    A. Berlin Wall is constructed
    B. Communist China joins the UN
    C. Soviet invasion of Czechoslovakia
    D. Berlin Blockade
    Choose the correct answer from the options given below:
  4. Morgenthau's principles of political realism are:
    A. Politics is rooted in permanent and unchanging human nature which is basically self centred, self-regarding and self-interested
    B. Politics is an autonomous sphere of action and cannot therefore be reduced to morals
    C. International Politics is an arena of conflicting self-interests
    D. The ethics of international relations is situational ethics which is very different from private morality
    Choose the correct answer from the options given below:

  5. Who among the following political thinkers consider the anarchical self help system to be a compelling factor for States to maximise their relative power positions?

Need Expert Advice?
Upcoming Exams
GATE
February 06, 2027
Test Series
CUET PG img
CUET
CUET PG Psychology (HUQP20) 2026 Mock Test Series
10 Tests
753 Attempts
3.7(14)
English
More Questions from CUET PG

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App