HNO3 + Ca —-> H2O + N20 + Ca(NO3)2
setup 1 : to the right
setup 2 : equilibrium
setup 3 : to the left
<h3>Further explanation</h3>
The reaction quotient (Q) : determine a reaction has reached equilibrium
For reaction :
aA+bB⇔cC+dD
![\tt Q=\dfrac{C]^c[D]^d}{[A]^a[B]^b}](https://tex.z-dn.net/?f=%5Ctt%20Q%3D%5Cdfrac%7BC%5D%5Ec%5BD%5D%5Ed%7D%7B%5BA%5D%5Ea%5BB%5D%5Eb%7D)
Comparing Q with K( the equilibrium constant) :
K is the product of ions in an equilibrium saturated state
Q is the product of the ion ions from the reacting substance
Q <K = solution has not occurred precipitation, the ratio of the products to reactants is less than the ratio at equilibrium. The reaction moved to the right (products)
Q = Ksp = saturated solution, exactly the precipitate will occur, the system at equilibrium
Q> K = sediment solution, the ratio of the products to reactants is greater than the ratio at equilibrium. The reaction moved to the left (reactants)
Keq = 6.16 x 10⁻³
Q for reaction N₂O₄(0) ⇒ 2NO₂(g)
![\tt Q=\dfrac{[NO_2]^2}{[N_2O_4]}](https://tex.z-dn.net/?f=%5Ctt%20Q%3D%5Cdfrac%7B%5BNO_2%5D%5E2%7D%7B%5BN_2O_4%5D%7D)
Setup 1 :

Q<K⇒The reaction moved to the right (products)
Setup 2 :

Q=K⇒the system at equilibrium
Setup 3 :

Q>K⇒The reaction moved to the left (reactants)
A strong base turns phenolphthalein pink, so the answer is (3) NaOH
Answer:
Roman numerals in a chemical formula indicate the charge on the metal cation before them. They are used in situations where the multiple oxidation states are available to the metal. For example, iron can be both 2+ and 3+, so to distinguish between the two, we use iron (II) and iron (III) respectively.
Hope i helped!
We classify them as follows:
1. 1 mol NaCl (s) à 1 mol NaCl(l)
C Molar heat of fusion; endothermic
2. C4H10 O(l) à C4H10O (g)
B Molar heat of vaporization; endothermic
3. H2O(g) à H2O (l)
D Molar heat of condensation; exothermic
4. 1 mol NaCl(s) + 3.88 kJ/molà 1 mol NaCl(aq)
A Molar heat of solution; endothermic