2024 CSAT — Q51

Locate. This asks for the best-supported inference (here, the implied suggestion), find the line that states the result and ask what practical use it points to. The passage: pumping a CO₂–water mix into basalt dissolved the rocks’ calcium and magnesium, “formed limestone,” and “Basically carbon dioxide is converted into stone.” The headline result is CO₂ locked into solid rock.

Test (find-the-line-then-match — what use does the result imply?). Converting CO₂ into stone is, by definition, capturing and storing carbon — carbon sequestration. (b) names exactly that practical suggestion and stays within what the passage demonstrates.

Eliminate by anatomy. (a) is too strong for what the passage says, and also a claim the passage never makes — “cheap… commercial… building purposes” adds economics and an end-use the passage never claims. (c) gets the direction backwards — the acid dissolved the rocks’ calcium and magnesium (consumed them); it did not turn basalt into a source of those minerals. (d) is a claim the passage never actually makes — producing rock-dissolving acid is a side detail, not the demonstrated point (storing CO₂). The transferable rule: the implied “suggestion” is the direct practical reading of the stated result — CO₂→stone means sequestration — not an economic or reversed extrapolation. Key: (b).

“Basically carbon dioxide is converted into stone, exclaimed the scientists” — locking CO₂ into stone is carbon sequestration, so the practical suggestion the passage implies is that the method can be used for carbon sequestration (b). (a) over-reaches (“cheap… commercial… building purposes” — none stated); (c) reverses the chemistry (the acid DISSOLVED the rocks’ calcium and magnesium — it did not make basalt a source of them); (d) misses the point (the aim is storing CO₂, not making acid).

The experiment turns CO₂ (mixed with water and pumped into basalt) into limestone — “carbon dioxide is converted into stone.” Locking atmospheric CO₂ into solid mineral form is precisely carbon sequestration.

(b) — the method can be used as carbon sequestration — is the practical suggestion the result implies. (a) adds unsupported claims of cheapness and commercial limestone for building; (c) reverses the chemistry (the rocks’ minerals were dissolved, not produced); (d) elevates a means (acid) over the demonstrated end (storing carbon).

Answer: (b).

The key reading is naming the result correctly: CO₂ → stone is carbon sequestration, so the implied practical use is sequestration (b). Each distractor mis-frames the same experiment — as an economic limestone process (a), as mineral extraction with the chemistry reversed (c), or as acid production (d). The scoring move is to keep the suggestion tethered to the demonstrated outcome rather than extrapolating cost, commerce, or a flipped reaction.