A solution of metal hydroxide `(MOH)` with copper sulphate and mixed tartarate of metal `M` with another metal `M_(1)` of the same group is used in the detection of `-CHO` froup. Metal `M` and `M_(1)` are respectively

Options

A. `K,Na`
B. `K,Rb`
C. `Na,Li`
D. `Rb,Na`

Explanation

To solve the question regarding the metals M and M1 used in the detection of the -CHO group, we can follow these steps:

### Step 1: Understanding the Detection Method
The question mentions that a solution of metal hydroxide (MOH) with copper sulfate (CuSO4) and mixed tartrate of metal M with another metal M1 is used for detecting the -CHO group. The -CHO group is characteristic of aldehydes.

### Step 2: Identifying the Reagent
The reagent commonly used for the detection of aldehydes is Fehling's solution, which consists of a mixture of two solutions: Fehling's A (copper(II) sulfate) and Fehling's B (a solution of sodium hydroxide and sodium tartrate). The reaction of the aldehyde with Fehling's solution results in the reduction of Cu²⁺ ions to Cu⁺ ions, forming a brick-red precipitate of copper(I) oxide (Cu2O).

### Step 3: Identifying Metal M and M1
In the context of Fehling's solution:
- The metal hydroxide (MOH) is sodium hydroxide (NaOH).
- The metal M is sodium (Na), and the metal M1 is potassium (K), which is also a part of the same group (alkali metals).

### Step 4: Conclusion
Thus, the metals M and M1 are:
- Metal M: Sodium (Na)
- Metal M1: Potassium (K)

### Final Answer
The metals M and M1 are respectively Sodium (Na) and Potassium (K).

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