In-text Questions — Occurrence and Extraction — Metals and Non-metals

1. 13 marksNCERT Cl-10 Science, In-text Qs after §3.4.2, Q1

   Define the following terms. (i) Mineral (ii) Ore (iii) Gangue

   Hint. One of these three words is a subset of another — every ore is one of the other two things, but not the reverse.

   Step 1 — Mineral. A mineral is an element or compound that occurs naturally in the earth's crust.

   Step 2 — Ore. An ore is a mineral in which a particular metal occurs in a high enough percentage that the metal can be profitably extracted from it — so every ore is a mineral, but not every mineral is concentrated enough to be called an ore.

   Step 3 — Gangue. Gangue is the unwanted impurities, such as soil and sand, present along with the ore, which must be removed before the metal can be extracted.

   ✦ Answer: Mineral — a naturally occurring element or compound in the earth's crust. Ore — a mineral rich enough in a metal to extract it profitably. Gangue — the impurities mixed with an ore that need to be removed.

   Where students slip. Treating 'mineral' and 'ore' as interchangeable — an ore is specifically a mineral with a high enough concentration of metal to be commercially worth extracting.

2. 21 markNCERT Cl-10 Science, In-text Qs after §3.4.2, Q2

   Name two metals which are found in nature in the free state.

   Hint. Think about the metals right at the bottom of the reactivity series.

   Step 1 — Recall which metals are least reactive. Metals at the bottom of the activity series are so unreactive that they don't combine with other elements in the earth's crust, so they occur as free elements.

   Step 2 — Name two. Gold (Au) and platinum (Pt) are both found in nature in the free (uncombined) state.

   ✦ Answer: Gold and platinum.

   Where students slip. Naming a moderately reactive metal like copper or silver as always 'free' — these do occur combined as sulphide or oxide ores too, unlike gold and platinum, which are essentially always found free.

3. 31 markNCERT Cl-10 Science, In-text Qs after §3.4.2, Q3

   What chemical process is used for obtaining a metal from its oxide?

   Hint. This is the general name for 'removing oxygen from' a compound.

   Step 1 — Name the process. Reduction is used to obtain a metal from its oxide, since it involves removing oxygen from the metal oxide to leave the free metal.

   ✦ Answer: Reduction.

   Where students slip. Naming 'roasting' or 'calcination' — those processes convert ores (sulphides or carbonates) into oxides; it's reduction that then converts the oxide into the metal itself.

Solutions written by the tuition.in editorial team and checked against the NCERT Class 10 Science textbook, Reprint 2026-27 (jesc103.pdf) — five in-text question sets (15 questions total, not 18 as some older manifests claim) plus one end-of-chapter Exercise (16 questions, correctly counted). Unchanged by rationalisation.. Questions are referenced from the NCERT textbook for identification.