WHAT IS SADAQAA?

Our Islamic scholars interpret both Zakat and Sadaqaa as charity. And whatever instruction Allah Almighty has given in the Quran in the following verse for Sadaqaat they attribute it to Zakat.

9:60 Indeed, the charities [Sadaqaat] are for the poor, and the needy, and those who work to collect them, and those whose hearts have been united, and to free the slaves, and those in debt, and in the cause of God, and the wayfarer. A duty from God, and God is Knowledgeable, Wise.

But, first of all, why would Allah Almighty use two different terms if they mean exactly the same thing? It does not make sense. Secondly, the Arabic language also does not support it. While the root meaning of Zakat comes from Z-K-W , meaning growth and development, the root meaning of Sadaqaa comes from the root S-D-Q , meaning truth and power. Therefore, all the words that are derived from this root will have these two meanings (truth and power) embedded in them. Siddeeq is one who proves his trust and belief by his actions. As-Sadaqatu is anything that is given in the way of Allah Almighty voluntarily to prove one’s promise and belief in Him as opposed to Zakat, which is compulsory [Tajul 'Uroos]. Therefore, Sadaqqa has a different purpose in Islam than Zakat and both cannot be equated with each other. How can income tax (a compulsory thing) be equated with charity (a voluntary thing)? .