A very dilute acidic solution of Cd2+ and Ni2+ gives only yellow ppt. of CdS on passing H2S, this is — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Soda extract (sodium carbonate extract) is prepared to bring anions of insoluble salts into a soluble form as sodium salts. Step 2: It is prepared by boiling the mixture with solid sodium carbonate (Na2CO3) in distilled water (typically in a 1:3 ratio) for 10-15 minutes, followed by filtration. Step 3: The boiling with Na2CO3 in distilled water promotes anion exchange to form soluble sodium salts and insoluble metal carbonates, corresponding to option (d).