Statements: All buildings are chalks. No chalk is toffee. Conclusions: i. No…

Concept:

When a universal affirmative statement (“All A are B”) is combined with a universal negative statement (“No B is C”) through the same shared middle term B, the two end terms A and C must be entirely disjoint — this yields a valid universal-negative conclusion, “No A is C.” Separately, a universal affirmative statement can only be partially converted: “All A are B” permits inferring “Some B are A,” never the full reversal “All B are A.”

Application:

1. Statement 1, “All buildings are chalks,” places the set of buildings entirely inside the set of chalks (Buildings ⊆ Chalks).

2. Statement 2, “No chalk is toffee,” excludes chalks and toffees entirely from each other (Chalks ∩ Toffees = ∅).

3. Combining these through the shared middle term “chalks” (a universal affirmative plus a universal negative) forces buildings and toffees apart as well, so conclusion (i), “No building is toffee,” is a guaranteed conclusion.

4. Conclusion (ii), “All chalks are buildings,” asks for the full reverse of Statement 1. A universal affirmative statement never licenses a full converse — only a limited “Some chalks are buildings” would be valid — so conclusion (ii) does not follow.

Cross-check:

• Venn diagram check: draw the chalks circle, place a smaller buildings circle fully inside it, and draw the toffees circle with no overlap with chalks at all. This single diagram satisfies both statements, and in it the buildings circle never touches the toffees circle — confirming conclusion (i) directly.

• The same diagram also shows the chalks circle can extend beyond the buildings circle (chalks need not equal buildings), so “All chalks are buildings” is not forced by the diagram — confirming conclusion (ii) does not follow.

Result: Only conclusion (1) follows.