| 1. | \(Na_4[Fe(CN)_5NOS]\) | 2. | \(Na_2[Fe(CN)_5NOS]\) |
| 3. | \(K_4[Fe(CN)_5NOS]\) | 4. | \(K_2 [Fe(CN)_4NOS]\) |
| 1. | \(\mathrm{Cl}^{-}\) | 2. | \(\mathrm{CO}_3{ }^{2-}\) |
| 3. | \( \mathrm{OH}^{-} \) | 4. | \( \mathrm{PO}_4{ }^{3-}\) |
| 1. | \(\mathrm { Dilute } ~\mathrm{HCl}\) | 2. | \(\mathrm{Dilute }~ \mathrm{HCl}+\mathrm{H} _2 \mathrm{S} \) |
| 3. | \( \mathrm{Dilute~ H_{2}SO_{4} }\) | 4. | \(\mathrm { Dilute } ~\mathrm{NH}_{ 4} \mathrm{OH}\) |
| 1. | Phenolphthalein | 2. | Methyl orange |
| 3. | Starch | 4. | None of the above |
Which color change is observed at the endpoint when oxalic acid is titrated with potassium permanganate?
| 1. | From pink to colourless | 2. | From pink to yellow |
| 3. | From pink to brown | 4. | From pink to purple |
| 1. | Oxidation | 2. | Reduction |
| 3. | Precipitation | 4. | Acid-base reaction |