Following metals are taken and each of them was tested for its reaction with cold water, hot water and steam: Zn,Al,Cu,Fe ,Mg,Na,K
Select the correct observations:
I. Na and K react violently with cold water.
II. Mg does not react with cold water but reacts with hat water.
III.Al, Zn and Cu react with steam
IV.Fe does not react with water or steam at all

Options

A. Both I and II
B. Both II and IIi
C. Both I and Iv
D. Both II and IV

Explanation

To solve the question regarding the reactions of various metals with cold water, hot water, and steam, we will analyze each observation step by step.

### Step 1: Analyze Observation I
**Observation I:** Na and K react violently with cold water.

- **Explanation:** Sodium (Na) and Potassium (K) are alkali metals. Alkali metals are known for their high reactivity, especially with water. When they react with cold water, they produce hydroxides and hydrogen gas, releasing a significant amount of heat, which can cause the hydrogen gas to ignite. Therefore, this observation is correct.

### Step 2: Analyze Observation II
**Observation II:** Mg does not react with cold water but reacts with hot water.

- **Explanation:** Magnesium (Mg) does not react with cold water due to the formation of a protective oxide layer on its surface. However, it can react with hot water to form magnesium hydroxide and hydrogen gas. Thus, this observation is also correct.

### Step 3: Analyze Observation III
**Observation III:** Al, Zn, and Cu react with steam.

- **Explanation:** Aluminum (Al) and Zinc (Zn) can react with steam to form their respective oxides and hydrogen gas. However, Copper (Cu) does not react with steam or any form of water. Therefore, this observation is incorrect because it includes Copper, which does not react.

### Step 4: Analyze Observation IV
**Observation IV:** Fe does not react with water or steam at all.

- **Explanation:** Iron (Fe) does not react with cold water, but it can react with steam to form iron oxide and hydrogen gas. Therefore, this observation is also incorrect.

### Conclusion
Based on the analysis:
- **Correct Observations:** I and II
- **Incorrect Observations:** III and IV

Thus, the correct answer is that observations I and II are correct.