Is it dangerous to drink liquore containing 42 percent achohal if has been opened for a period of time?

It's not inherently dangerous to drink liquor that has been opened for a period of time, as long as it has been stored properly.

Here's what you need to consider:

Factors affecting liquor quality over time:

* Storage: Liquor should be stored in a cool, dark place. Exposure to heat, light, and air can cause it to deteriorate.

* Type of liquor: Some liquors, like fortified wines, are more susceptible to oxidation and can lose flavor and quality faster.

* Seal: A well-sealed bottle will retain its quality for longer.

* Time: The longer the liquor is open, the more it's exposed to the elements, and the more likely it is to lose flavor and quality.

Signs of deterioration:

* Change in color: The color may become duller or have a cloudy appearance.

* Change in smell: The aroma may be muted, or you may notice a vinegary or oxidized smell.

* Change in taste: The flavor may be less intense or have a bitter or metallic taste.

Important note: While drinking slightly degraded liquor is unlikely to be dangerous, it won't be as enjoyable. It's always best to enjoy your liquor fresh!

Recommendation:

If you're unsure about the quality of an opened bottle of liquor, it's best to err on the side of caution and discard it. Enjoy your liquor responsibly!