The boiling points of hydrides of group 16 are in the order

Options

A. `H_(2)O lt H_(2)S lt H_(2)Se lt H_(2) Te`
B. `H_(2)Te lt H_(2)Se lt H_(2)S lt H_(2)O`
C. `H_(2)S lt H_(2)Se lt H_(2) Te lt H_(2)O`
D. `H_(2)O lt H_(2) Te lt H_(2)Se lt H_(2)S`

Answer

To determine the boiling points of the hydrides of group 16 elements, we will analyze the hydrides H2O, H2S, H2Se, and H2Te step by step.

### Step 1: Identify the Group 16 Hydrides
The hydrides of group 16 elements include:
- H2O (water)
- H2S (hydrogen sulfide)
- H2Se (hydrogen selenide)
- H2Te (hydrogen telluride)

### Step 2: List the Boiling Points
The boiling points of these hydrides are:
- H2O: 373 K
- H2S: 213 K
- H2Se: 232 K
- H2Te: 269 K

### Step 3: Analyze the Boiling Points
1. **H2O** has a significantly higher boiling point compared to the other hydrides. This is primarily due to the presence of strong intermolecular hydrogen bonding in water.
2. **H2S, H2Se, and H2Te** do not exhibit hydrogen bonding to the same extent as H2O because sulfur, selenium, and tellurium are less electronegative than oxygen. Therefore, their boiling points are lower.

### Step 4: Understand Trends in Boiling Points
- As we move down the group from H2O to H2Te, the boiling points initially decrease from H2O to H2S, then increase from H2S to H2Te.
- The decrease from H2O to H2S is due to the absence of hydrogen bonding in H2S.
- The increase from H2S to H2Te can be attributed to the increase in molecular size and the corresponding increase in Van der Waals forces of attraction.

### Step 5: Establish the Order of Boiling Points
Based on the analysis:
- The boiling points can be ordered as follows:
- H2O > H2Te > H2Se > H2S

### Final Order
Thus, the boiling points of the hydrides of group 16 are in the order:
**H2O > H2Te > H2Se > H2S**