Question

which solution will change red litmus paper to blue?
a. hcl because it gives of h⁺ ions
b. nacl because it gives off cl⁻ ions
c. ch₃oh because it gives off ch₃ ions
d. naoh because it gives off oh⁻ ions

Explanation:

To determine which solution turns red litmus paper blue, we recall that bases (substances releasing $\ce{OH^-}$ ions) do this.

• Option A: $\ce{HCl}$ releases $\ce{H^+}$ (acid), red litmus stays red.
• Option B: $\ce{NaCl}$ is neutral (releases $\ce{Na^+}$ and $\ce{Cl^-}$), no litmus change.
• Option C: $\ce{CH3OH}$ (methanol) is organic, doesn’t release $\ce{CH3^+}$ ions (and is neutral).
• Option D: $\ce{NaOH}$ releases $\ce{OH^-}$ (base), so red litmus turns blue.

Answer:

D. NaOH because it gives off $\ce{OH^-}$ ions