<u>Answer:</u> The mass of solid NaOH required is 80 g
<u>Explanation:</u>
Equivalent weight is calculated by dividing the molecular weight by n factor. The equation used is:

where,
n = acidity for bases = 1 (For NaOH)
Molar mass of NaOH = 40 g/mol
Putting values in above equation, we get:

Normality is defined as the umber of gram equivalents dissolved per liter of the solution.
Mathematically,

Or,
......(1)
We are given:
Given mass of NaOH = ?
Equivalent mass of NaOH = 40 g/eq
Volume of solution = 400 mL
Normality of solution = 5 eq/L
Putting values in equation 1, we get:

Hence, the mass of solid NaOH required is 80 g
Salt dissolved in water is a solution, therefore
- salt is not chemically bonded to water
- the ratio of salt to water may vary
- salt and water retain their own chemical properties
<u>Explanation:</u>
Salt (sodium chloride) is formed from positive sodium ions bonded to negative chloride ions. Water can dissolve salt because the positive part of water particles attracts the negative chloride ions of salt. The water particle effects to be charged negatively near the atom of oxygen and positively near the atom of hydrogen.
Since contrasts attract, the water molecules tend to join collectively like magnets. Water is called the universal solvent since it can solve more substances than any other liquid. The salt and water retain their unique chemical properties.
Some physical properties that a pencil would have is, color, density, texture, hardness (in this case the lead is soft). phase (liquid,solid gas), shape, size. physical properties describe the look and feel of a substance. I hope this helps
Why is hydrogen a “cleaner” fuel source than gasoline?
hydrogen is natural created and in the air already, gas is a fossil fuel and is killing the Ozone layer. carbon dioxide is a poison and can really harm us and the world.
this paragraph basically explains the question
Compared to the carbon dioxide that is produced when we burn gasoline, ethanol, and other carbon-containing fuels, the water produced by burning hydrogen has a less harmful effect on Earth’s climate. If we can power our cars with hydrogen without producing carbon dioxide, then why don’t more vehicles use hydrogen fuel? Unfortunately, the technology needed to use hydrogen as a fuel is expensive, and storing hydrogen fuel can be difficult. Also, the most common way of getting pure hydrogen is by separating it from substances that contain carbon—so although burning hydrogen fuel does less harm to Earth’s climate than burning carbon-containing fuels, the production of hydrogen fuel is still a problem for scientists trying to reduce climate change.