General Q&A for Class 12 · Page 168
5,215 free answers in General for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What is 0.3 of an hour?
0.3 of an hour equals 18 minutes. Multiply 0.3 × 60 minutes = 18 minutes. This conversion is essential when working with decimal time in speed, distance, and time calculations.
- GeneralClass 12All
How do you calculate 7.6 hours?
7.6 hours equals 7 hours and 36 minutes. To convert the decimal: multiply 0.6 by 60 minutes = 36 minutes. So 7.6 hours = 7:36 in time format. This is useful when converting decimal time from calculations into standard hours and minutes.
- GeneralClass 12All
What is the 80/20 rule for 5K training?
The 80/20 rule suggests that 80% of your running should be at an easy, conversational pace, while 20% should be at moderate to high intensity. For 5K training, this means most runs build aerobic base at a comfortable speed, while shorter sessions include intervals, tempo runs, or race-pace efforts to develop speed and lactate threshold.
- GeneralClass 12All
Is it possible to run 60 km in 4 hours
Yes, but it's extremely challenging. This requires maintaining 15 km/h (4 minutes per kilometer) for four hours straight, which is an elite ultramarathon pace. While physiologically possible for top athletes, it demands exceptional endurance, training, and mental fortitude.
- GeneralClass 12All
How many km is a 30-minute run?
This depends on your running speed. At a moderate pace of 10 km/h, you would cover 5 km in 30 minutes. Beginners (8 km/h) might cover 4 km, while faster runners (12 km/h) could complete 6 km in the same time.
- GeneralClass 12All
What pace is a 20-minute 5K?
A 20-minute 5K equals a pace of 4 minutes per kilometer or 6 minutes 26 seconds per mile. This is an excellent time for recreational runners and requires significant training and natural ability. The running speed is 15 km/h.
- GeneralClass 12All
How to run 10 km in 1 hour?
To run 10 km in 1 hour, you need to maintain a pace of 6 minutes per kilometer or about 9 minutes 40 seconds per mile. This requires running at a steady speed of 10 km/h. Build up gradually through consistent training, incorporating interval work, tempo runs, and long slow distance runs to develop the necessary endurance and speed.
- GeneralClass 12All
What pace is a 45-minute 10K?
A 45-minute 10K run equals a pace of 4 minutes 30 seconds per kilometer or approximately 7 minutes 15 seconds per mile. This corresponds to a speed of 13.3 km/h and represents a solid recreational running performance that many runners train months to achieve.
- GeneralClass 12All
Is 1 km in 4 minutes fast?
Yes, 1 km in 4 minutes is very fast. This equals a pace of 4 minutes per kilometer, which translates to 15 km/h or a sub-17 minute 5K. This pace is competitive for recreational runners and requires good cardiovascular fitness and training.
- GeneralClass 12All
What is 3.0×10⁸ in physics?
This is the speed of light, expressed in scientific notation as 3.0×10⁸ m/s (meters per second). This fundamental constant appears in many physics equations, most famously in E=mc², where it relates energy and mass. Nothing with mass can travel at or faster than this speed.
- GeneralClass 12All
What is weak acid?
A weak acid is a substance that only partially dissociates into ions when dissolved in water, meaning only a small fraction of its molecules release hydrogen ions (H+). Acetic acid is a classic example – in solution, most molecules remain intact as CH3COOH, with only a small percentage ionizing. Weak acids have higher pH values (typically 3-6) than strong acids, are less corrosive, and establish an equilibrium between their molecular and ionized forms in solution.
- GeneralClass 12All
Is acetic acid used for cleaning?
Yes, acetic acid is widely used for cleaning, primarily in its diluted form as vinegar. It effectively removes mineral deposits, soap scum, hard water stains, and grease from various surfaces. The acid dissolves calcium carbonate buildup, making it excellent for cleaning coffee makers, kettles, and showerheads. It also has mild antibacterial properties. Household white vinegar (5% acetic acid) is safe for most cleaning tasks, while higher concentrations (10-20%) are used in some commercial cl
- GeneralClass 12All
Is vinegar 100% acetic acid?
No, vinegar is not 100% acetic acid. Household vinegar typically contains 4-7% acetic acid, with the remainder being water and trace compounds that provide flavor and aroma. White distilled vinegar usually has 5% acetic acid content, which is the standard for most culinary uses. Specialty vinegars like apple cider, wine, or balsamic vinegars contain similar acetic acid levels but include additional organic compounds from their source materials. Industrial-grade vinegar may have higher concent
- GeneralClass 12All
Is acetic acid better than vinegar?
Acetic acid and vinegar aren't directly comparable as "better" or "worse" – they serve different purposes. Vinegar (4-7% acetic acid in water with other compounds) is safer for cooking, cleaning, and consumption. Pure acetic acid (glacial acetic acid) is more concentrated and effective for industrial applications, laboratory work, and specialized uses, but it's dangerous and corrosive. For household cleaning, vinegar is preferable due to safety; for industrial chemical processes, pure a
- GeneralClass 12All
Is acetic acid in curd?
Curd (yogurt) contains small amounts of acetic acid produced by bacteria during fermentation, though lactic acid is the predominant acid present. During the fermentation process, various bacteria including some acetobacter species can produce acetic acid alongside lactic acid. However, the acetic acid content is much lower than the lactic acid content. The primary bacteria in most yogurt cultures produce lactic acid, which gives curd its characteristic tangy flavor and thick texture, while ac
- GeneralClass 12All
What are the benefits of drinking acetic acid?
Drinking diluted acetic acid (such as in apple cider vinegar) may offer several potential health benefits. Research suggests it may help regulate blood sugar levels, improve insulin sensitivity, and support weight management by increasing feelings of fullness. It may aid digestion by increasing stomach acid production and promoting beneficial gut bacteria. Some studies indicate potential benefits for heart health through improved cholesterol levels. However, it's crucial to consume only prope
- GeneralClass 12All
Is acetic acid safe to eat in food?
Yes, acetic acid is safe to eat in food when used in appropriate concentrations. It's recognized as Generally Recognized As Safe (GRAS) by food safety authorities worldwide when consumed in typical amounts found in foods and vinegar. The diluted form in vinegar (4-7% acetic acid) has been consumed safely for thousands of years. However, concentrated acetic acid (above 10%) can cause burns and should never be consumed directly. In normal dietary amounts, acetic acid poses no health risks and m
- GeneralClass 12All
Is vinegar called sirka?
Yes, vinegar is called "sirka" in Hindi, Urdu, and several other South Asian languages. The term is widely used across India, Pakistan, and neighboring regions to refer to vinegar in cooking and household contexts. Both white vinegar and various specialty vinegars used in South Asian cuisine are referred to as sirka. The word is commonly seen in recipes for pickles (achar), chutneys, and various traditional dishes where vinegar serves as a preservative and flavoring agent.
- GeneralClass 12All
Is boiling vinegar safe?
Boiling vinegar can be safe when done properly with adequate ventilation, but it releases acetic acid vapors that can irritate eyes, nose, throat, and respiratory system. The vapors are particularly harsh in enclosed spaces. If boiling vinegar for cleaning purposes (like removing burnt food or deodorizing), ensure windows are open and use exhaust fans. Brief, well-ventilated boiling is generally safe, but prolonged exposure to concentrated vapors should be avoided. Never boil concentrated ace
- GeneralClass 12All
What is the nickname for acetic acid?
The most common nickname for acetic acid is "glacial acetic acid" when referring to the pure, concentrated form (99-100% purity). This term comes from its property of forming ice-like crystals when cooled. In diluted form (4-7%), acetic acid is simply called "vinegar." In chemical industries, it might be referred to as "ethanoic acid" (its IUPAC systematic name) or abbreviated as "AcOH" or "HOAc" in chemical equations. These various names help distinguish between different concentrations and