Institution: Directorate of Nursing Services (DNS) Exam: ডিপ্লোমা ইন নার্সিং ভর্তি পরীক্ষা। ২০২২-২০২৩ || নার্সিং(Nursing) ভর্তি পরীক্ষা || 2023
Topic: Chemistry (রসায়ন), Subject: General Science (সাধারণ বিজ্ঞান)

Best Answer Explained in Below-:

The question 'তুঁতের সংকেত কোনটি?' translates to 'What is the formula for copper sulfate?' in English. Among the options given:

A) N a H C O 3 (Sodium bicarbonate)
B) C u S O 4 (Copper sulfate)
C) N a 2 S O 4 (Sodium sulfate)
D) F e S O 4 (Ferrous sulfate)

The correct choice is B) C u S O 4, which is the chemical formula for copper(II) sulfate, commonly known as blue vitriol or cupric sulfate. It consists of one copper atom (Cu), one sulfur atom (S), and four oxygen atoms (O4), making it a key compound in various applications, including agriculture, chemistry, and even educational demonstrations due to its distinctive blue color.

The other options represent different compounds:
- A) NaHCO3 is sodium bicarbonate, used as a leavening agent.
- C) Na2SO4 is sodium sulfate, a drying agent and in detergents.
- D) FeSO4 is ferrous sulfate, used in water treatment and as a dietary supplement.

Given that the question specifically asks for the formula associated with copper sulfate, option B) C u S O 4 is the accurate and relevant choice.