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MHT-CET Chemistry · Elements of Group 1 and 2

Hydrogen and H₂O₂, the Solvay Process, Minerals and Alloys

The chapter's applied facts: how pure hydrogen, water gas and hydrogen peroxide are made, what the Solvay process recycles and leaves behind, and which formula or metal pair a mineral or alloy stands for.

All Elements of Group 1 and 2 notesMHT-CET Chemistry strategy

Why this matters

15 PYQs, all EASY or MODERATE, and every one a named fact — hydrogen and H₂O₂ (6), the Solvay process and lime (3), minerals, alloys and uses (6). Three tables to learn.

Concept 1 of 3: Dihydrogen, Water Gas and Hydrogen Peroxide

Each method is a pair to learn: the method and what it gives. The purest hydrogen comes from electrolysing warm barium hydroxide solution; steam over hot coke gives water gas, CO + H₂; and the shift reaction then turns the CO into more H₂ over an Fe–Cr catalyst.

Definition

  • H₂ purer than 99.5%: electrolysis of warm aqueous Ba(OH)₂ with Ni electrodes.
  • Water gas: C + H₂O → CO + H₂.
  • Water-gas shift (~500 °C): CO + H₂O ⇌ CO₂ + H₂, catalyst Fe–Cr (iron chromate).
  • Haber process: Fe catalyst with Mo promoter.
  • Merck process for H₂O₂: Na₂O₂ + cold dilute H₂SO₄.
  • H₂O₂: pale blue in the pure state; miscible with water in all proportions; strength given in volumes; oxidising AND reducing agent.
Process or factAnswer
H₂ with purity > 99.5%Electrolysis of warm aq. Ba(OH)₂Q
Water gasCO + H₂Q
Catalyst for CO + H₂O ⇌ CO₂ + H₂ at 500 °CFe–CrQ
Catalyst in the Haber processMo/FeQ
H₂O₂ by Merck process — starting materialNa₂O₂Q
H₂O₂ and waterMiscible in all proportionsQ
Practice this conceptself-check

The same idea in a real exam question:

MHT-CET · 2025 · 22 April Shift I · Q92Moderate

Example 1 · Elements of Group 1 and 2 · Industrial Processes, Minerals, Hydrogen Compounds and Alloys

Identify the catalyst used in following reaction at 500∘C500^{\circ}C ?
CO+H2O⇌CO2+H2CO +H_{2}O \rightleftharpoons CO_{2}+H_{2}
Drill 5 more on dihydrogen, water gas and hydrogen peroxide

Concept 2 of 3: The Solvay Process and Slaked Lime

Solvay makes sodium carbonate from brine, ammonia and CO₂. The expensive ammonia ends up as NH₄Cl, so slaked lime is added to get it back — which is why calcium chloride is the process's waste product.

Definition

  • NaCl + NH₃ + CO₂ + H₂O → NaHCO₃↓ + NH₄Cl; NaHCO₃ is heated to Na₂CO₃.
  • Ammonia recovery: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O.
  • By-product: CaCl₂.
  • CO₂ through lime water: Ca(OH)₂ + CO₂ → CaCO₃↓ (milky).
QuestionAnswer
Recovered when NH₄Cl meets slaked limeNH₃Q
By-product of the Solvay processCalcium chlorideQ
CO₂ bubbled through slaked limeCaCO₃ precipitateQ
Practice this conceptself-check

The same idea in a real exam question:

MHT-CET · 2023 · 15th May Shift 1 · Q93Moderate

Example 2 · Elements of Group 1 and 2 · Industrial Processes, Minerals, Hydrogen Compounds and Alloys

Which from following compounds is obtained as by product in synthesis of sodium carbonate by Solvay process?

Picking ammonium chloride as the by-product

NH₄Cl forms, but it is not thrown away — it is treated with lime to get the ammonia back. What remains is CaCl₂.
Drill 2 more on the solvay process and slaked lime

Concept 3 of 3: Minerals, Alloys and Uses

Pure recall: a mineral's formula, an alloy's two metals, and the element each use needs.

Definition

  • Galena PbS; zinc blende ZnS; gypsum CaSO₄·2H₂O; baryte BaSO₄.
  • Carnallite KCl·MgCl₂·6H₂O; cleveite contains uranium (radioactive), and is a source of helium.
  • Brass Cu + Zn; bronze Cu + Sn (statues, medals, trophies).
  • Radium — cancer radiotherapy.
NameComposition or use
GalenaPbSQ
CarnalliteKCl·MgCl₂·6H₂OQ
CleveiteContains radioactive uraniumQ
BrassCu + ZnQ
Bronze (trophies)Cu + SnQ
RadiumCancer treatmentQ
Practice this conceptself-check

The same idea in a real exam question:

MHT-CET · 2024 · 12th May Shift 1 · Q56Easy

Example 3 · Elements of Group 1 and 2 · Industrial Processes, Minerals, Hydrogen Compounds and Alloys

Which of the following is an alloy of copper and zinc?

Brass or bronze

Brass is copper and ZINC; bronze is copper and TIN. Both are offered together every time.
Drill 5 more on minerals, alloys and uses

Summary — formulas & gotchas at a glance

A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.

Reference tables (3)

Dihydrogen, Water Gas and Hydrogen Peroxide6 rows
Process or factAnswer
H₂ with purity > 99.5%Electrolysis of warm aq. Ba(OH)₂Q
Water gasCO + H₂Q
Catalyst for CO + H₂O ⇌ CO₂ + H₂ at 500 °CFe–CrQ
Catalyst in the Haber processMo/FeQ
H₂O₂ by Merck process — starting materialNa₂O₂Q
H₂O₂ and waterMiscible in all proportionsQ
The Solvay Process and Slaked Lime3 rows
QuestionAnswer
Recovered when NH₄Cl meets slaked limeNH₃Q
By-product of the Solvay processCalcium chlorideQ
CO₂ bubbled through slaked limeCaCO₃ precipitateQ
Minerals, Alloys and Uses6 rows
NameComposition or use
GalenaPbSQ
CarnalliteKCl·MgCl₂·6H₂OQ
CleveiteContains radioactive uraniumQ
BrassCu + ZnQ
Bronze (trophies)Cu + SnQ
RadiumCancer treatmentQ

Watch out for (2)

Test yourself on Elements of Group 1 and 2

15 past MHT-CET questions from this chapter, timed at 14 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.

Take the Elements of Group 1 and 2 chapter testDrill all 15 questions

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