MCQ
Which is a buffer solution
- ✓$C{H_3}COOH + C{H_3}COONa$
- B$C{H_3}COOH + C{H_3}COON{H_4}$
- C$C{H_3}COOH + N{H_4}Cl$
- D$NaOH + NaCl$
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| Element | Atomic mass |
| $A$ | $12.01$ |
| $B$ | $35.5$ |
$A$ and $B$ combine to form new substance $X$ . If $4\,moles$ of $B$ combine with $1\,mole$ of $A$ to give $1\,mole$ of $X,$ then weight of one mole of $X$ is ........... $\mathrm{g}$
$\Delta E = - 2.0 \times {10^{ - 18}}\,J\left( {\frac{1}{{n_2^2}} - \frac{1}{{n_1^2}}} \right)$
the wavelength of the light that must be absorbed to excite hydrogen electron from level $n\, = 1$ to level $n\, = 2$ will be: $(h\, = 6.625\times10^{-34}\, J\,s,\, C\, = 3\times10^8\, m\,s^{-1})$
Reason : The presence of additional $d-$ electron offer poor screening effect for the outer electrons from increased nuclear charge.